Production of Cell Wall Degrading Enzymes and Toxins by Colletotrichum Capsici and Alternaria Alternata Causing Fruit ROT of Chillies

Abstract

Abstract:The virulent isolates of Colletotrichum capsici and Alternaria alternata produced more cellulolytic enzymes viz., C 1 and C x in vitro than the avirulent ones and the activity of these enzymes increased with the increase in age of culture. The virulent isolates of C. capsici and A. alternata produced more pectinolytic enzymes (macerating enzymes, pectin methyl esterase and endo polygalacturonase) than the avirulent ones. All the pectinolytic enzymes were highly active in 10-day-old culture and the activities decreased with the increase of culture age. Whereas the activity of enzymes produced by avirulent isolate of pathogens did not decrease and these enzyme activities increased with the increase in the age of culture. These pathogens also produced nonspecific toxic metabolites in culture filtrate which reduced seed germination, root length, shoot length and vigour index of the seedlings of chilli, rice, mungbean, maize, cotton, groundnut, okra, egg plant, cucumber and tomato.The toxins of the pathogens reduced seed germination and caused mortality of chilli seedlings in pot culture. The toxins also produced phytotoxic symptoms in the treated ripe and green chilli fruits and leaves.

Screening of biological activities of fungi associated with pistachio bark beetle, Chaetoptelius vestitus (Coleoptera, Curculionidae), infesting pistachio cultivations in Tunisia

“…In this study, fungal isolates Nqu_io_1 ( N. quercina ) , Aal_io_1 (A. alternata ) , Mgu_io_1 ( M. guilliermondii ) , Apr_io_1 ( A. protuberus ) , Ave_io_1 ( A. versicolor ) , Tat_io_1 ( T. atroroseus ), Tpi_io_1 ( T. pinophilus ) as well as all Penicillium isolates showed a cellulolytic activity. These results are consistent with previous studies presenting most of these species ( A. alternata, M. guilliermondii, Aspergillus protuberus, Aspergillus versicolor and T. pinophilus ) as having cellulolytic potential (Anand et al ; Qaisar et al ; Yun et al ; Suresh Yadav et al ; Li et al ; Vaishnav et al ). Previous studies have reported that cellulolytic activity positively affected phytopathogenicity by facilitating fungal penetration through the host cell wall which mainly include cellulose (Wanjiru et al ; Keegstra ).…”

Silicon‐mediated cell wall modifications of sorghum root exodermis and suppression of invasion by fungus Alternaria alternata

“…The penetration process of this fungus occurs directly through plant surfaces (by mechanical and/or chemical means), through natural openings in plants or openings due to wounding. Several enzymes might contribute to the infection establishment and progress, including cutinases, cellulases, pectinases, lipases, galacturonidases and endoglucanases (Thomma, and references therein; Anand et al ., ). Alternaria species also possess the ability to produce a broad spectrum of toxins, both host‐nonspecific and host‐specific (for reviews, see Thomma, ; Tsuge et al ., ).…”

Evaluation of virulence and pathogenicity of Alternaria patula on French marigold (Tagetes patula)

“…citri were found to be necessary for pathogenesis (Isshiki et al ., ). Alternaria alternata causes fruit rot of chillies via the production of cellulase, which degrades cellulose, and pectinolytic enzymes, including PMEs and endo‐PGs (Anand et al ., ). Thus, as found in the present study for A. patula , pectin degradation requires the combination of several pectinases generated by the pathogen during plant infection.…”