Use Of Genetics and Biotechnological, Etiological, And Epidemiological Research for Rice Improvement

INVESTIGATOR: Rush, M. C.

PERFORMING INSTITUTION:
Plant Pathology & Crop Physiology
Louisiana State University
Baton Rouge, Louisiana 70803

NON-TECHNICAL SUMMARY: Diseases are a major constraint on rice production in Louisiana. This project will identify or develop resistances to major rice diseases and transfer them to breeding lines with the agronomic characteristics of commercial varieties.

OBJECTIVES: 1. To develop and/or transfer new or novel sources of disease and stress resistance in rice through the use of somaculture, cell culture, in vitro cell selection, protoplast culture, pollen culture, transformation, and other tissue culture and related techniques. This would include the development of in vitro screening methods for selecting resistance to pathogens, pathogen toxins, and other toxic constraints to rice production. 2. To modify rice for resistance to disease, toxins, or other biological constraints by transformation with DNA from plasmids with known structure or DNA from plants with nonhost resistance to these constraints. 3. To locate and maintain sources of disease and stress resistance in Oryza sativa L., Oryza spp., and related graminaceous species for use in rice improvement. 4. To identify mechanisms of resistance in rice to major rice pathogens, to elaborate the mode-of action of these mechanisms, and to study the inheritance of genes controlling disease resistance and resistance mechanisms. 5. To utilize conventional breeding techniques to develop rice lines with desirable disease resistance characteristics and tolerance to toxic constraints, combined with desirable plant type and yield characteristics, for use in the Louisiana State University Agricultural Experiment Station rice breeding program conducted at the LSU-LAES Rice Research Station.

APPROACH: Techniques for regenerating plants from protoplasts, and for in vitro cellular level studies will be developed or modified as necessary to carry out the objectives of this project. We have already developed a somaculture system that allows us to regenerate as many somaclones as desired. Variation for disease and stress resistances, developed through wide-crosses, somaculture, cell culture, and other methods for introducing foreign DNA, will be studied as necessary to ensure that resistance obtained through these experiments is incorporated into breeding or elite lines of suitable plant type and with suitable grain quality. We have developed a system for in vitro screening of protoplasts against toxic constraints on rice growth. This system will be used to develop cell lines of commercial varieties resistant to several toxins produced by P. oryzae and R. solani, herbicides, and other toxic stress factors. Non-host resistance to sheath blight will be characterized by comparison of the infection process between susceptible and resistant rice cultivars and the non-host. Procedures are being developed and evaluated to transfer DNA from plants other than rice. Transformation of rice with plasmid DNA will be accomplished in accordance with NIH guidelines and field testing of transformed plants and their progeny will be conducted under permits from the USDA and the Louisiana Department of Agriculture and Forestry. Data from 25 years of field screening nurseries will be evaluated to select entries with resistance to major rice diseases. Crosses will be made to study inheritance of the resistance and to accumulate resistance genes in rice lines with good plant type. Selected entries will be studied to identify mechanisms giving resistance and to elaborate the modes-of-action involved. Foreign O. sativa cultivars and lines, Oryza spp., and related graminaceous species will be screened in greenhouse and field tests for resistance to major rice diseases. Methods will be developed to transfer identified resistances to rice with commercial plant-type. Wide-crosses, in vitro hybridization; introduction of foreign chromosome pieces or DNA through callus, protoplasts, pollen, or immature ovaries and other systems will be studied to attempt to transfer Oryza resistance or non-host resistance to rice transgenically. We have identified several sources of sheath blight resistance; including our new somaclonal variants, several lines from a rice x wild grass hybrid collected by M.C. Rush in China in 1980 (rice/grass), the H4/CODF line obtained from screening nurseries in the 1970s, and the varieties Jasmine 85, Leah, Katy, Tetep, Tadukan, Gui Chao,Teqing, Yang Dao 4, and Yang Dao 6. This material and other resistant rice cultivars will be used in a modified recurrent selection procedure to develop a large number of breeding lines with useful agronomic characteristics, high yield potential, acceptable grain quality, and high levels of sheath blight resistance. Modes-of inheritance of these resistances will be determined.

KEYWORDS: rice diseases |x nomatch; tissue culture; transformation; disease resistance; breeding; clonal variation |x nomatch

PROGRESS: 2004/01 TO 2004/12
A total of 15,936 progeny rows were planted and inoculated with Rhizoctonia solani in 2004 for disease resistance evaluations. Also, 354 advanced sheath blight resistant lines were selected to obtain grain quality and yield data in the joint breeding/pathology yield test in 2005. The 2004 yield test was conducted with six control varieties to test 52 breeding lines selected in 2003. Six check varieties were planted as controls to test 51 lines. The lines were grown in yield plots using a split-plot design with two replicates. In each replicate one plot (split) was inoculated with R. solani and one plot was not inoculated (healthy rice). The lines and varieties were rated at maturity. Lines were more SB resistant than varieties, except for Pirogue which had good SB resistance. Healthy Pirogue yielded 8511lb/A while Pirogue with SB yielded 7738lb/A, for a 9.1% loss to SB. Cocodrie yielded 8616lb/A /5689lb/A for a 33.9% loss to SB. Two high yielding SB resistant lines, MCR3-0007 (8994lb/A / 7983lb/A) and MCR3-3086 (8038lb/A / 7496lb/A), will be included in the 2005 Uniform Rice Nursery. Line MCR 02-1534 is being increased by the breeding program. F2 populations from crosses made with several SB resistant transgenic Taipei 309 plants, having transgenes for chitinase or beta glucanase production, and Cocodrie were grown in 2004. Populations were inoculated and individual plants rated for resistance to SB. F2 populations had plants segregating for SB resistance. Progeny from these plants will be backcrossed to Cocodrie to develop further F2 populations for screening in field tests. Bacterial panicle blight (BPB), caused by Burkholderia glumae, is a continuing problem in Louisiana rice when night-time temperatures are high. A 217 entry BPB nursery for screening for resistance was planted. Each plot was inoculated as the panicles began to emerge and were rated at maturity for BPB. Eleven (5.5%) of the 200 URN entries were resistant to BLB with ratings of less than 4.0 on the 0-9 rating scale. Several lines previously identified as resistant to BPB were also resistant in 2004. They were Nipponbare (NPB), LM-1, AB647, RU0202183, RU0103190, and RU0103153. NPB, LM-1, AB647 and LR2065 were reciprocally crossed with Cocodrie and each other in 2003-2004. F2 populations were grown in the field. Random panicle selections will be planted in 2005 as F3 panicle rows. Field isolates of BiologTM identified Burkholderia spp. had identities further confirmed by PCR and fatty acid analysis, using ATCC cultures as controls. Among the 292 Burkholderia spp. tested, 242 and 13 isolates reacted positively with B. glumae and B. gladioli primers, respectively. Studies to develop ELISA and PCR tests for identifying infected seed-lots and PCR tests for identifying plants infected with Burkholderia species were continued. Bacterial DNA isolated from fresh panicle blight infected green tissue and from seed-extracts reacted with B. glumae and B. gladioli monoclones in ELISA tests and with primers in PCR tests. B. gladioli, but not B. glumae, was demonstrated to be both seedborne and soilborne. Temperature optima were determined for B. glumae (38-40C) and B. gladioli (35-37C).

IMPACT: 2004/01 TO 2004/12
Development of cultivars resistant to sheath blight and bacterial panicle blight would increase the income of rice growers by about 12 million dollars through increased yields and reduced costs for fungicides.

PUBLICATIONS: 2004/01 TO 2004/12
1. Oard, S., Rush,M.C., Oard,J.H. 2004. Characterization of antimicrobial peptides against a US strain of the pathogen Rhizoctonia solani. Journal of Applied Microbiology 97: 169-180.
2. Chu, Q.R., Groth, D.E., Rush, M.C., Linscombe, S.D., and Shao, Q.M. 2004. Development of sheath blight resistant lines through doubled haploid technology. Proc. of the 30th Rice Technical Working Group Meeting. Feb. 29-31. New Orleans, Louisiana. p.114.
3. Groth, D.E., Dunand, R.T., Hollier, C.A., Rush, M.C., and Shao, Q. 2004. Bakanae-like symptoms produced by gibberellic acid in Louisiana. Proc. of the 30th Rice Technical Working Group Meeting. Feb. 29-31. New Orleans, Louisiana. p.116.
4. OReilly, K.L., Triche, P.C., Harden, T.T., Nandakumar, R. and Rush, M.C. 2004. Abstract BP5. Development of a monoclonal antibody based ELISA for the detection of Burkholderia glumae, the causative agent of panicle blight in rice. South Central Branch of the Amer. Soc. for Microb., Starkville, MS, November 5.
5. Pinson, S.R.M., Shahjahan, A.K., and Rush, M.C. 2004. QTLs for panicle blight resistance - and their association with resistance to other diseases. Proc. of the 30th Rice Technical Working Group Meeting. Feb. 29-31. New Orleans, Louisiana. p.81.
6. Rush, M.C., Shao,Q.M., Zhang,S., Shahjahan,A.K.M., OReilly,K., Shih,D., Groth,D. and Linscombe,S.D. 2004. Biotechnology and control of rice diseases. Louisiana Agriculture 46: 20-22.
7. Rush, M., Shahjahan, A., Shuli, Z., Yuan, X., Clark, C., Groth,D., OReilly, K., Cartwright, R., Marchetti, T. 2004. Bacterial panicle blight and sheath rot disease of rice in the Southern United States. World Rice Research Conference. Nov. 5-7. p.357.
8. Rush, M., Shao, Q., Sha, X., Zhang, S., Groth, D., Xie, Q., Linscombe, S. 2004. Developing resistance to sheath blight in rice based on partial resistance. World rice Research Conference. Nov. 5-7. p.357.
9. Rush, M.C., Shao, Q.M., Shahjahan, A.K.M., and Groth, D.E. 2004. Screening rice varieties and lines for reaction to bacterial panicle blight caused by Burkholderia glumae. Proc. of the 30th Rice Technical Working Group Meeting. Feb. 29-31. New Orleans, Louisiana. p.121.
10. Shao, Q.M. Rush, M.C., Xiao, Y., Zhang, S.L., Groth, D.E. and Linscombe, S.D. 2004. Rice sheath blight control using liberty herbicide as a fungicide on transgenic Cypress rice. Proc. of the 30th Rice Technical Working Group Meeting. Feb. 29-31. New Orleans, Louisiana. p.37.
11. Shao, Q.M., Rush, M.C., Wu, M.S., Zhang, S.L., Groth, D.E., and Linscombe, S.D. 2004. Linkage breaking between Liberty resistance (bar) and hygromycin resistance (hpt) genes by selection of transgenic Taipei 309 plants. Proc. of the 30th Rice Technical Working Group Meeting. Feb. 29-31. New Orleans, Louisiana. p.65.
12. Yuan, X.L., Shahjahan, A.K.M., and Rush, M.C. 2004. The agents causing bacterial panicle blight disease on rice in Louisiana: a complex of Burkholderia spp. Proc. of the 30th Rice Technical Working Group Meeting. Feb. 29-31. New Orleans, p.120.
13. Zhang, S.L., Shi, Y.L., Zhang, Y.H., Shao, O.M., Shih, D., and Rush, M.C. 2004. The development of rice sheath blight resistance using transformation of pathogenesis related protein genes. Proc. of the 30th Rice Technical Working Group Meeting. Feb. 29-31. New Orleans, Louisiana. p.39.
14. Zhang, S.L., Shi, Y.L., Shao, O.M., Shih, D., and Rush, M.C. 2004. Transformation of rice with the thionin gene for bacterial panicle blight resistance. Proc. of the 30th Rice Technical Working Group Meeting. Feb. 29-31. New Orleans, Louisiana p.6.

PROGRESS: 2003/01/01 TO 2003/12/31
A total of 18,400 progeny rows were planted in 2003 for disease studies. Field evaluations of germplasm for sheath blight (SB) resistance included 5565 progeny rows from F4 and higher generations, 11,120 F3 progeny rows, and 750 rows of F2 populations. Seventy four new crosses were made during 2003. Fifty-nine advanced SB resistant lines were collected for use in the 2004 SB yield test. The 2003 yield test had 77 SB resistant lines and nine check cultivars. A split-plot design for yield potential, SB losses, and quality characteristics was used. The SB resistant lines showed higher resistance than the check cultivars, except for Earl. Experimental lines MCR02-6322 and MCR02-0766 had the highest composite yields (8862 and 8845 lb/A). Eleven lines had composite plot yields higher than the Cocodrie check (7535 lbs/A). Two inoculated lines (infected) had higher yields than the non-inoculated (healthy) Cocodrie. Sixteen resistant lines (21%) yielded more in the inoculated plots than the non-inoculated plots. Three entries from the 2002 yield test were placed by the breeding program in the 2003 URN tests and by us in the 2003 bacterial panicle blight (BPB) nursery. BPB ratings for the resistant control LM-1 was 1.7 and 6.7 for the susceptible control Francis. For the three lines in the URN, the ratings were 3.3(URN 143),6.7(URN 152), and 3.6(URN 155). URN 143 yielded very well in the Louisiana and Arkansas URN plantings. Our research for developing sheath blight resistance also involves using biotechnology techniques to incorporate disease resistance PR protein genes for production of glucanase and chitinase enzymes and thionin into rice. We transformed 79 Taipei 309 plants with the beta-1,3-glucanase and chitinase genes and transplanted these plants to the field, inoculated them with R. solani, and evaluated them for SB resistance. Several of the transformed plants were highly resistant to SB. We crossed these plants with Cocodrie to study inheritance of the resistance and to transfer the resistance to lines with commercial characteristics. Taipei 309 plants transformed for thionin production also were successfully field tested, with resistant plants crossed to Cocodrie. A permit was obtained from USDA, APHIS, by submitting a Release Notification Letter. A nursery was planted to screen 200 URN entries plus five resistant controls for BPB resistance. Each entry had three rows per replication,and three replications. The middle row of each plot was inoculated with Burkholderia glumae isolate 951886-4-1c. The percentage of panicles infected and a panicle blight rating (0-9 scale) were recorded for each entry. Thirty (14.6 %) entries in the nursery were resistant to BPB. Three entries previously tested and found resistant; AB647, Nipponbare, and LM-1, were highly resistant in the 2003 nursery. Crosses were made with the resistant materials and Cocodrie. Evaluation of bacterial isolates from BPB infected rice in Louisiana showed that B. glumae, B. gladioli, B. multivorans, B. cepacia, and B. planterii were all pathogenic on rice and may be involved in a complex of Burkholderia species causing BPB in Louisiana.

IMPACT: 2003/01/01 TO 2003/12/31
Development of cultivars resistant to sheath blight and bacterial panicle blight would increase the income of rice growers by about 12 million dollars through increased yields and reduced costs for fungicides.

PUBLICATIONS: 2003/01/01 TO 2003/12/31
1. Shao, Q.M., M.C. Rush, D. E. Groth, and S. D. Linscombe. 2003. Potential for using Liberty herbicide as a fungicide to control sheath blight of rice on transgenic cultivars. Louisiana Plant Protection Association & Louisiana Association of Agronomy, Baton Rouge, LA. Pp13.
2. Shao, Q.M., S. D. Linscombe, D. E. Groth, Y. Xiao, and M.C. Rush. 2003. Effect of liberty applications on hyphal growth of R. solani in vitro and on transgenic rice as determined by electron microscopy. Louisiana Plant Protection Association & Louisiana Association of Agronomy, Baton Rouge, LA. Pp12.
3. Rush, M.C., Q.M. Shao, S.D. Linscombe, and D.E. Groth. 2002. Development of sheath blight resistance in rice. 94th Annual Research Report, Rice Research Station, Louisiana Agricultural Experiment Station. (Published in 2003)

PROGRESS: 2002/01/01 TO 2002/12/31
More than 20,000 rows were planted in 2002 for disease resistance evaluations. Ninety five sheath blight(SB) resistant lines were advanced to the joint breeding/pathology yield test in 2003. One hundred fifty two crosses were made during 2002. A yield test was carried out with 46 lines and the cultivars Bengal, Cocodrie, Cypress, Earl, Francis, Saber, and Wells. Most of the lines showed higher SB resistance than the cultivars, except for Earl, which has excellent resistance. Line MCR00-0219 had the highest yield in both the 2001 and 2002 yield tests. Three lines were advanced by the breeding program to the uniform yield nursery grown in Arkansas, Mississippi, Louisiana, and Texas. Efforts to transfer the bar gene from transformed Taipei 309 and Nipponbare rice into the commercial rice cultivars Lafitte, Cypress, Drew, Katy, Lemont, Jodon, and Maybelle, was continued with a yield test using 19 selected backcross lines and five of the recurrent parents. A split-plot design was used with the split plots sprayed or not sprayed with Liberty. These lines showed very similar phenotypes to the backcross parents, but with a high level of resistance to Liberty herbicide. Several lines had yields equal to or higher than the recurrent parents. Spraying with Liberty at later growth stages caused significant injury and loss to some lines. These results demonstrate that single-gene controlled variation, induced by transformation with a foreign gene, could be transferred by crossing and backcrossing to commercial cultivars in 3 years or less. A third year of field testing to study control of rice SB with Liberty herbicide sprays had thirty eight rate and timing treatments. Three years of field trials confirmed that Liberty was fungicidal and gives control of SB equal to or better than that given by the commercial fungicides Moncut or Quadris when the proper rates and timings of applications were used. Bacterial panicle blight (BPB) is a recurrent problem in rice in Louisiana when the temperature and humidity are above 95C and 90% R.H. The causal bacterium, Burkholderia glumae, is seedborne. Isolates from infected seeds were variable in culture characteristics and in utilization of various nitrogen and carbon sources. Our studies on monoclonal antibody production show that B. glumae specific antiserum can be developed and used to detect the pathogen in seed-lots. Two experiments were conducted in 2002 to screen for BPB resistance and to compare B. glumae isolates for virulence. In a 160 entry inoculated, screening nursery, about 1% of the entries were resistant. Entries AB 649, LM-1, and LA2065, were resistant in both 2001 and 2002. Some isolates of B. gladioli also caused panicle blighting and sheath rotting in our tests. A single isolate of B. cepacia was highly virulent on rice in inoculation studies. B. plantarii and B. fuscovaginae were also isolated from infected rice. Studies on detection of B. glumea from seeds showed that the bacterium could be isolated from one infected seed, suggesting that bacterial populations were high enough that monoclonal antibodies produced from B. glumae will be able to detect the presence of the bacterium in seed-lots.

IMPACT: 2002/01/01 TO 2002/12/31
This research is directed toward reducing losses in yield of rice grown in Louisiana through development of disease resistance and other methods of controlling disease. Expected benefit is approximately 10 million dollars a year to Louisiana rice growers.

PUBLICATIONS: 2002/01/01 TO 2002/12/31
1. Cheng, G., A.K.M. Shahjahan, L.Y. Yuan, and M.C. Rush. 2002. Distinguishing among isolates of Burkholderia glumae, B. gladioli, B. plantarii, and B. cepacia from rice. Proc.29th Rice Tech. Working Group. Little Rock, AR. February 24-27, 2002. P. 94.
2. Cheng G., M.C. Rush, and A.K.M. Shahjahan. 2002. Studies on the pathogen causing panicle blight of rice in Louisiana, distinguishing among isolates of Burkholderia glumae, B. gladioli, B. plantarii, and B. cepacia from rice. 93rd Ann. Res. Rep., Rice Res. Station, Louisiana Agricultural Experiment Station. Pp. 376-378.
3. Rush, M.C., Q.M. Shao, and D. Groth. Developing sheath blight resistance in rice. Proc. LA. Plant Prot. Assoc. and LA. Assoc. of Agron. April 1-2, 2002. P. 67.
4. Rush, M.C., S.D. Linscombe, X.Y. Sha, and Q.M. Shao. 2002. Current status of our research on developing sheath blight resistance in rice. Proc. 29th Rice Tech. Working Group. Little Rock, AR. February 24-27, 2002. P. 89.
5. Rush, M.C., A.K.M. Shahjahan, and D.E. Groth. 2001. Field evaluation of chemicals for controlling bacterial panicle blight of rice. 93rd Ann. Res. Rep., Rice Res. Station, Louisiana Agricultural Experiment Station. Pp. 370-375. (Published in 2002)
6. Rush, M.C., Q.M. Shao, S.D. Linscombe, and D.E. Groth. 2001. Development of sheath blight resistance in rice. 93rd Ann. Res. Rep., Rice Res. Station, Louisiana Agricultural Experiment Station. Pp. 370-375. (Published in 2002)
7. Shahjahan, A.K.M., M.C.Rush, and D.E. Groth. 2001. Field nursery screening of rice germplasm for resistance to bacterial panicle blight. 93rd Ann. Res. Rep., Rice Res. Station, Louisiana Agricultural Experiment Station. Pp. 381-382. (Published in 2002)
8. Shao, Q.M., D. Groth, and M.C. Rush. 2002. Potential for rice sheath blight control using Liberty herbicide. Proc. LA. Plant Prot. Assoc. and Louisiana Assoc. of Agron. April 1-2, 2002. P. 65.
9. Shao, Q.M, S.D. Linscombe, and M.C. Rush. 2002. Allelic analysis of transgenic rice plants from `Taipei 309' and `Nipponbare'. Proc. 29th Rice Tech. Working Group. Little Rock, AR. February 24-27, 2002. P. 61.
10. Shao, Q.M., D.E. Groth, S.D. Linscombe, and M.C. Rush. 2002. Potential for rice sheath blight control using Liberty herbicide. Proc.29th Rice Tech. Working Group. Little Rock, AR. February 24-27, 2002. P. 92.
11. Wu, M.S., Q.M. Shao, and M.C. Rush. 2002. Molecular analysis of rice plants transformed with the genes for resistance to Liberty Herbicide and hygromycin B. Proc. 29th Rice Tech. Working Group. Little Rock, AR. February 24-27, 2002. P. 61.
12. Wu, M.S. Q.M. Shao, and M.C. Rush. 2002. Molecular analysis of rice plants transformed with the genes for resistance to Liberty herbicide and hygromycin B. Proc. LA. Plant Prot. Assoc. and LA. Assoc. of Agron.. April 1-2, 2002. P. 66.
13. Zhang, S.L., X.Y. Shih, S.D. Gao, X. Wu, and M.C.Rush. 2002. Co-Transformation of the bar and thionin genes into rice. Proc. 29th Rice Tech. Working Group. Little Rock, AR. February 24-27, 2002. P. 61.

PROGRESS: 2001/01/01 TO 2001/12/31
A total of 19,844 rows were evaluated for disease resistance in 2001. Thirty nine advanced sheath blight resistant lines were transferred to the breeding program to obtain grain quality and yield data in a joint breeding/pathology test. One hundred sixty crosses were made to combine partial SB resistance from different sources into progeny rows. In the 2001 yield test using 39 experimental lines and the five check cultivars Bengal, Cocodrie, Cypress, Earl, and Maybelle, a split-plot design for yield and losses due to SB was used. Most of the lines showed much higher SB resistance than the check cultivars and had higher yields. Twelve inoculated lines (infected) had higher yields than the non-inoculated (healthy) Cypress. Resistant lines had less than 10% loss in inoculated plots (2.4-9.6% loss),whereas, Cypress averaged 18.8% loss in the inoculated plots and Cocodrie averaged 32.9% loss. About 25 of 100 Cocodrie lines, derived from tissue culture, appeared to be resistant to SB. Other clonal variation, including changes in height and heading date, were also observed among these lines. The effort to transfer the bar gene from stable R3 lines of transformed Taipei 309 and Nipponbare rice into commercial rice cultivars, which include Lafitte, Cypress, Drew, Katy, Lemont, Jodon, and Maybelle, was continued through 2001. A yield test was carried out using 19 backcross lines along with the five parents Lafitte, Cypress, Lemont, Katy, and Maybelle. These lines showed very similar phenotypes to the backcross parents and have the same yield potential, but with a high level of resistance to Liberty herbicide. A total of 30 treatments, with four replications, were included in a field test to study control of rice SB with Liberty sprays. The results confirmed that Liberty gave increasing control of sheath blight with increasing rates of Liberty. Transgenic Teqing plants with the bar gene were resistant to Liberty in field tests during 2000 and 2001. Several short transgenic Teqing lines were selected and will be retested in 2002. F1 plants from 616 crosses were grown in the field in 2001. Seeds from these plants will be used to grow F2 populations in 2002. Panicle blight, caused by the bacterium Burkholderia glumae, is a recurrent problem of rice in Louisiana. The disease is seedborne and unusually high temperature appears to be conducive to its development. The disease also has been prevalent in the neighboring states of Arkansas and Texas. Experiments were conducted at the Rice Research Station in Crowley to test the effectiveness of different chemicals as seed treatment and foliar sprays against the panicle blight disease, to evaluate the reactions of rice cultivars and breeding lines against B. glumae in field nurseries, and to study the effect of planting infected seeds on panicle blight development and yield of rice. We also continued studies on developing monoclonal antibody systems for identifying seed infected with B. glumae and quantifying the amount of bacteria in a seedlot.

IMPACT: 2001/01/01 TO 2001/12/31
The objective of this research is to control the sheath blight disease of rice using disease resistance. This disease is the most severe disease constraint on rice in Louisiana and in the Gulf of Mississippi rice production area. We also are focusing on a newly identified disease, bacterial panicle blight. Together, these diseases cause millions of dollars in direct loss, and in costs of control measures, to Louisiana rice growers. By identifying the cause of bacterial panicle blight, we have made it possible to research control measures for this previously unidentified disease.

PUBLICATIONS: 2001/01/01 TO 2001/12/31
1. Rodrigues F. A., L.E. Datnoff, G.H. Korndorfer, K.W. Seebold, and M.C. Rush. 2001. Effect of silicon and host resistance on sheath blight development in rice. Plant Dis. 85:827-832.
2. Shahjahan, A. K. M., M. C. Rush, and D. E. Groth. 2001. Phylloplane yeasts as potential biocontrol agents for rice sheath blight disease. Pp.235 -252. In: S. Sreenivasaprasad and R. Johnson, (Ed.), Major Fungal Diseases of Rice Recent Advances. Kluwer Academic Publishers, Netherlands.

PROGRESS: 2000/01/01 TO 2000/12/31
About 14,300 rows were planted at the Louisiana State University Agricultural Center Rice Research Station in Crowley, Louisiana in 2000 for various disease resistance evaluations. A total of 72 advanced SB resistant lines were transferred to the breeding program to obtain grain quality data. More than 640 crosses were made to combine partial SB resistance from different sources into progeny rows for future selection. A yield test was carried out in cooperation with the breeding program,using 38 experimental lines along with the five check cultivars Bengal, Cocodrie, Cypress, Lafitte, and Maybelle. These lines were tested for yield potential, losses due to SB, and quality characteristics. Most of the lines showed much higher SB resistance than the check cultivars and yielded the same or higher than the check cultivars. Resistant lines had less than 10% loss in inoculated plots (2.59-8.76% loss),whereas, Cypress averaged 21.2% loss and Cocodrie averaged 38.2% loss. The effort to transfer the bar gene from stable, homozygous R3 lines of transformed Taipei 309 and Nipponbare rice into commercial rice cultivars was continued in 2000. About 50 homozygous backcross 4/5 experimental lines with stable resistance to Liberty herbicide were selected for planting in 2000. The backcross parents Lafitte, Lemont, Cypress, and Katy were used as controls. A total of 18 lines, from back-crosses representing all backcross parents, were selected for yield tests in 2001. These lines, obtained in 2.5 to 3 years, were very similar to the backcross parents, but with a high level of resistance to Liberty herbicide. A preliminary field test with 84 treatments was conducted to study the effectiveness of Liberty herbicide for control of the sheath blight, blast, and bacterial panicle blight diseases in transgenic Cypress rice. Liberty had poor residual effect and did not control these diseases when applied before inoculations. Applications made after inoculation gave increasing control of sheath blight with increasing rates of Liberty. If Liberty controls pathogens in rice fields when sprayed for weed control, it will greatly increase the usefulness of this compound in rice. A thionine gene, which codes for low molecular weight polypeptide thionins with antimicrobial activities, was introduced into the rice cultivars Cypress and Taipei 309 through particle bombardment of calli derived from mature seeds in 1999. We are developing homozygous populations for field tests in 2001. In 2000 we transformed an additional Taipei 309 plant and six Lafitte plants with the thionine gene. We believe this gene has the potential to control bacterial panicle blight, bacterial leaf blight, and several fungal diseases of rice. Approximately 15,000 progeny rows selected in 2000 will be planted and evaluated for SB and blast resistance in 2001. Direct co-transformation of commercial cultivars with the bar and thionine genes is continuing. The effectiveness of thionins against pathogens causing sheath blight, blast, and panicle blight is being tested in the greenhouse.

IMPACT: 2000/01/01 TO 2000/12/31
Much of our research is related to controlling the sheath blight disease of rice using disease resistance. This disease is the most severe disease constraint on rice in Louisiana and in the Gulf of Mississippi rice production area. We also are focusing on a newly identified disease, bacterial panicle blight. Together these diseases cause millions of dollars in direct loss, and in costs of control measures, to Louisiana rice growers.

PUBLICATIONS: 2000/01/01 TO 2000/12/31
1. Chen, C., D.E. Groth, Q.M. Shao, and M.C. Rush. 2000. Phytotoxicity of thiobencarb and it's dechlorinated product to rice. Proc. Rice Tech. Work. Group 28:76. (Biloxi,MS: Feb.27-March 1,2000)
2. Chen, C., D.E. Groth, N.M. Huffstetler, H.F. Morris, and M.C. Rush. 2000. Microbes associated with dechlorination of thiobencarb in a specific south Louisiana rice field soil. Proc. Rice Tech.Work.Group 28:79-80. (Biloxi,MS: Feb.27-March 1,2000)
3. Chu, Q.R., S.D. Linscombe, H.X. Cao, D.E. Groth, M.C. Rush, and J. Oard. 1999. Rice anther culture breeding. Ann.Res. Rept., Rice Res. Sta., LA State Univ. Agri. Centr. 91: 506-548. (published in 2000)
4. Dunand, R.T., M.C. Rush, R.R. Dilly, Jr., and A.K.M. Shahjahan. 1999. Panicle blight study. Ann. Res. Rept., Rice Res. Sta., La State Univ. Agri. Centr. 91: 313-316. (published in 2000)
5. Groth, D.E., M. Frey, J. Nugent, C. Chen, M.C. Rush, A.K.M. Shahjahan, P.K. Bolich, and S.D. Linscombe. 1999. Rice disease control studies,1999. Ann. Res. Rept., Rice Res. Sta., LA State Univ. Agri. Centr. 91: 357-415. (published in 2000)
6. Groth, D.E., A.K.M. Shahjahan, and M.C. Rush. 2000. Chemical control of panicle blight of rice. Proc.Rice Tech. Work. Group 28:79. (Biloxi,MS: Feb.27-March 1,2000)
7. Rush, M.C., X.Y. Sha, Q.M. Shao, S.D. Linscombe, and D.E. Groth. 1999. Development of sheath blight resistance in rice. Ann. Res. Rept., Rice Res. Sta., LA State Univ. Agri. Centr. 91: 56-79.(published in 2000)
8. Rush, M.C., A.K.M. Shahjahan, and D.E. Groth. 1999. In-vitro and in-vivo evaluation of chemicals for controlling rice panicle blight caused by Burkholderia glumae (Kurita et Tabei). Ann. Res. Rept., Rice Res. Sta., LA State Univ. Agri. Centr. 91: 416-427. (published in 2000)
9. Rush, M.C., A.K.M. Shahjahan, and D.E. Groth. 2000. Potential for management of panicle blight through seed treatment and foliar application of pesticides. Proc. Rice Tech. Work. Group 28:81. (Biloxi,MS:Feb.27-March 1,2000)
10. Shahjahan, A.K.M., D.E. Groth, C.A. Clark, S.D. Linscombe, and M.C. Rush. 2000. Epidemiological studies on panicle blight of rice: critical stage of infection and the effect of infected seeds on disease development and yield of rice. Proc. Rice Tech. Work. Group 28:77. (Biloxi,MS: Feb.27-March 1,2000)
11. Shao, Q.M., S.D. Linscombe, E.C. Achberger, and M.C. Rush. 2000. Inheritance of the Bar and hygromycin genes in transformed Taipei 309 and Nipponbare. Proc. Rice Tech. Work. Group 28:46. (Biloxi,MS: Feb.27-March 1,2000)
12. Shao, Q.M., S.D. Linscombe, X.Y. Sha, and M.C. Rush. 2000. Transfer of the Bar gene from transgenic Taipei 309 and Nipponbare into U.S. commercial rice varieties through repeated backcrosses. Proc. Rice Tech. Work. Group 28:53. (Biloxi,MS: Feb.27-March 1,2000)

PROJECT CONTACT:
Name: Rush, M. C.
Phone: 225-388-1464
Fax: 225-388-1415
Email: mrush@agctr.lsu.edu  

[previous page]