Development of conventional and real-time PCR protocols for specific and sensitive detection of Colletotrichum capsici in chilli (Capsicum annuum L.)     

Madhavan Srinivasan  Satya Vijayalakshmi Kothandaraman  Paranidharan Vaikuntavasan  Velazhahan Rethinasamy 《Phytoparasitica》2014,42(4):437-444

Anthracnose, caused by Colletotrichum capsici, is a major disease of chilli (Capsicum annuum L.) affecting both fruit and seed quality. The pathogen is both internally and externally seedborne. However, a rapid and sensitive method for detection of this pathogen in seeds is currently limited. In this study, a polymerase chain reaction (PCR) method based on sequence characterized amplified region (SCAR) marker was developed for specific and sensitive detection of C. capsici in chilli seeds and fruits. The developed SCAR primers were highly specific to C. capsici and resulted in the amplification of an expected 250-bp fragment from genomic DNA of all seven of the C. capsici isolates tested. No amplification occurred when the SCAR primers were tested with genomic DNA from three other fungal isolates and four other Colletotrichum species. The SCAR primers successfully amplified similar sized fragments from DNA derived from C. capsici-infected chilli fruits. The molecular detection sensitivity of C. capsici was 1 pg of purified C. capsici DNA template and 25 ng of DNA from C. capsici-infected chilli fruits. A real-time PCR assay was also developed using SYBR Green chemistry for detection of C. capsici in chilli fruits and seeds. The standard curve obtained showed a linear correlation between copy number of the cloned target DNA sequence of C. capsici and cycle threshold (Ct) values, with R² of 0.98. These PCR-based assays may be highly useful in detection of this important pathogen in chilli seeds and fruits in plant quarantine laboratories.  相似文献   

Host-Specific Toxin Production by Rhizoctonia solani, the Rice Sheath Blight Pathogen     

Vidhyasekaran P  Ponmalar TR  Samiyappan R  Velazhahan R  Vimala R  Ramanathan A  Paranidharan V  Muthukrishnan S 《Phytopathology》1997,87(12):1258-1263

ABSTRACT Rhizoctonia solani, the rice sheath blight pathogen, produces a toxin that reproduces all symptoms of the disease. The toxin has been partially purified and it was found to be a carbohydrate containing glucose, mannose, N-acetylgalactosamine, and N-acetylglucosamine. The toxin was also detected in infected leaves. Highly virulent isolates produced more toxin than less virulent isolates. Several R. solani isolates from rice and one each from cotton and tomato produced a similar toxin. All rice cultivars tested were susceptible to the pathogen and sensitive to the toxin. Host specificity of the toxin has been demonstrated using hosts and nonhosts of the pathogen.  相似文献   

Assessment of mungbean genotypes for durable resistance to Yellow Mosaic Disease: Genotype × Environment interactions          下载免费PDF全文

Ashok K. Parihar  Ashwani K. Basandrai  Asmita Sirari  Dakshinamurthy Dinakaran  Deepak Singh  Kamala Kannan  Kailash P. S. Kushawaha  Maddineni Adinarayan  Mohammad Akram  Tnpalayam Krshnaswamy S. Latha  Vaikuntavasan Paranidharan  Sanjeev Gupta 《Plant Breeding》2017,136(1):94-100

Yellow mosaic disease (YMD) is the major constraint of mungbean for realizing high productivity worldwide. Moreover, management of disease using YMD‐resistant genotypes is the simplest approach. Therefore, based on a preliminary screening of 220 genotypes during the year 2010 and 2011 at 17 locations, a set of 25 genotypes was further selected to evaluate at six locations over 2 years for identification of more stable resistant genotypes. The genotype and genotype × environment (GGE) analysis indicated that the genotypes and environment effects were significant (P < 0.001) for YMD incidence. Interestingly, the GGE biplot analysis successfully accounted for 74.71 per cent of the total variation with three genotypes (ML 818, ML 1349 and IPM 02‐14) showing high degree of resistance and stability over the locations. Notably, a strong positive association was observed between disease reaction and temperature, relative humidity and rainfall. As crop is grown in diverse growing environments, aforementioned genotypes can be used as stable/durable sources for future breeding programme to develop YMD‐resistant cultivars.  相似文献   

RAPD and virulence analyses of Colletotrichum capski isolates from chilli (Capsicum annuum)     

Madhavan  Srinivasan  Paranidharan  Vaikuntavasan  Velazhahan  Rethinasamy 《植物病害和植物保护杂志》2010,117(6):253-257

Journal of Plant Diseases and Protection - Chilli (Capsicum annuum) fruits showing symptoms of an-thracnose disease were collected from farmer’s fields in different chilli-growing areas of...  相似文献   

Induction of systemic resistance byPseudomonas fluorescens Pf1 againstXanthomonas oryzae pv.Oryzae in rice leaves     

P. Vidhyasekaran  N. Kamala  A. Ramanathan  K. Rajappan  V. Paranidharan  R. Velazhahan 《Phytoparasitica》2001,29(2):155-166

When lower leaves of rice plants were inoculated with powder formulation of a saprophytic strain ofPseudomonas fluorescens, Pfl, upper leaves, in addition to the inoculated lower leaves, showed resistance to the rice bacterial blight pathogenXanthomonas oryzae pv.oryzae. When the leaves were challenge-inoculated withX. oryzae pv.oryzae 4 days afterP. fluorescens application on lower leaves, the disease intensity in upper leaves decreased from 6.7 to 1.1. When rice seeds were treated with the formulation ofP. fluorescens Pfl and sown, 30-day-old seedlings showed resistance toX. oryzae pv.oryzae and the disease intensity decreased from 6.8 to 1.2. The induced resistance was transient; leaves sprayed withP. fluorescens Pfl at 30 days after treatment and leaves of 60-day-old seedlings fromP. fluorescens-treated seeds did not show resistance to the pathogen. In field trials, seed treatment followed by foliar application of the powder formulation ofP. fluorescens Pfl effectively controlled rice bacterial blight and increased the yield. In the induced resistant leaves a sharp increase in lignification and activities of peroxidase, phenylalanine ammonia-lyase and 4-coumarate: CoA ligase was observed when the leaves were challenge-inoculated withX. oryzae pv.oryzae. An approximately threefold increase in lignin content, peroxidase activity and phenylalanine ammonia-lyase activity and a fivefold increase in 4-coumarate: CoA ligase activity were observed 5 days after challenge inoculation withX. oryzae pv.oryzae in rice leaves pretreated withP. fluorescens for 5 days. A similar increase in defense-related activities was not observed in susceptible interactions or inP. fluorescens-treated plants at later stages of interactions when no resistance to the pathogen was observed.  相似文献