Authors:W.J. Chi, Z.Y. Wang, J.M. Liu, C. Zhang, Y.H. Wu, and Y.J. Bai
Nitrogen (N) is an important nutrient for plant growth and yield production, and rice grown in paddy soil mainly uses ammonium (NH4+) as its N source. Previous studies have shown that N status is tightly connected to plant defense; however, the roles of NH4+ uptake and assimilation in rice sheath blight disease response have not been studied previously. Here, we analyzed the effects of different N sources on plant defense against Rhizoctonia solani. The results indicated that rice plants grown in N-free conditions had higher resistance to sheath blight than those grown under N conditions. In greater detail, rice plants cultured with glutamine as the sole N source were more susceptible to sheath blight disease compared to the groups using NH4+ and nitrate (NO3–) as sole N sources. N deficiency severely inhibited plant growth; therefore, ammonium transporter 1;2 overexpressors (AMT1;2 OXs) were generated to test their growth and defense ability under low N conditions. AMT1;2 OXs increased N use efficiency and exhibited less susceptible symptoms to R. solani and highly induced the expression of PBZ1 compared to the wild-type controls upon infection of R. solani. Furthermore, the glutamine synthetase 1;1 (GS1;1) mutant (gs1;1) was more susceptible to R. solani infection than the wild-type control, and the genetic combination of AMT1;2 OX and gs1;1 revealed that AMT1;2 OX was less susceptible to R. solani and required GS1;1 activity. In addition, cellular NH4+ content was higher in AMT1;2 OX and gs1;1 plants, indicating that NH4+ was not directly controlling plant defense. In conclusion, the present study showed that the activation of NH4+ uptake and assimilation were required for rice resistance against sheath blight disease.
Authors:S. Babu, R. Nandakumar, S. Sriram, R. Jaisankar, V. Shanmugam, T. Raguchander, R. Samiyappan, and P. Balasubramania
Sriram, S., Raguchander, T., Vidhyasekaran, P., Muthukrishnan, S. and Samiyappan, R. (1997): Genetic relatedness with special reference to virulence among the isolates of Rhizoctonia solani causing sheathblight in rice. J. Plant Dis. Protect. 104, 260
Authors:S. Naeimi, S. Kocsubé, Zsuzsanna Antal, S. Okhovvat, M. Javan-Nikkhah, C. Vágvölgyi, and L. Kredics
Naeimi, S. (2010) Development of a Specific Molecular Marker for Detection of the Most Effective Trichoderma Strain Against Thanatephorus cucumeris, the Causal Agent of Rice SheathBlight Disease . PhD thesis, Faculty of Agriculture, University of
Authors:B. Chen, L.-W. Li, Y.-J. Lin, Z.-H. Wang, and G.-D. Lu
Rice sheath blight, caused by Rhizoctonia solani, is the most serious disease in the southern rice producing regions of China. The use of resistant varieties is the most economic strategy to control the disease. In this paper, a seedling inoculation method was used to evaluate rice germplasm resources for resistance to sheath blight. A total of 363 rice varieties were evaluated with a set of R. solani isolates. The results indicated that the rice varieties generally lacked resistance to R. solani, and no highly resistant/immune (HR) variety was found. However, two varieties displayed clear resistance (R) and 37 showed moderate resistance (MR) to the fungus. Overall, hybrid rice varieties have better resistance than conventional rice varieties, and among hybrid rice varieties, those with the II-32A sterile line genetic background were the most resistant. The results also indicated significant interactions between rice varieties and pathogen isolates, suggesting that an understanding of local R. solani populations is needed when recommending varieties to local growers.
Authors:S. Mathiyazhagan, K. Kavitha, G. Chandrasekar, S. Nakkeeran, K. Manian, A. S. Krishnamoorthy, A. Sankaralingam, and W. G. D. Fernando
., Sriram, S., Babu, S., Jaisankar, R., Xu, R., Muthukrishnan, S., Prakash, Om and Velazhahan, R. (1997): Enzymatic degradation of Rhizoctonia toxin involved in sheathblight disease of rice. In: General Meeting of the International Program on Rice
Authors:C. Bharathimatha, Sabitha Doraiswamy, and R. Velazhahan*
Lin, W., Anuratha, C. S., Datta, K., Potrykus, I., Muthukrishnan, S. and Datta, S. K. (1995): Genetic engineering of rice for resistance to sheathblight. Bio/Technology 13, 686-691.
Genetic engineering of rice for resistance