Biohardening of Tissue Cultured Banana Plantlets of cv. Ney Poovan for the Management of Fusarium wilt of Banana with Bacillus amyloliquefaciens (VB7) Triggers Defence Gene Products and Growth Promotion
C. Y. Shalini Udaya
Department of Fruit Science, Horticultural College & Research Institute, Tamil Nadu Agricultural University, Coimbatore, India.
S. Nakkeeran
Department of Plant Biotechnology, Centre for Plant Molecular Biology and Bioinformatics, Tamil Nadu Agricultural University, Coimbatore, India.
K. Soorianathasundaram
*
Controllerate of Examinations, Tamil Nadu Agricultural University, Coimbatore, India.
*Author to whom correspondence should be addressed.
Abstract
Fusarium wilt of banana is the most devastating disease caused by Fusarium oxysporum f.sp. cubense (Foc). In order to combat the early onset of Fusarium wilt disease, an experiment was carried out on biohardening of tissue cultured plantlets. Six bacterial endophytes were observed to inhibit the growth of Foc in vitro. Among the six bacterial endophytes, Bacillus amyloliquefaciens (VB7) inhibited mycelial growth of Foc to an extent of 70.58% over control. Further, these bacterial endophytes were used for biohardening of the tissue cultured banana plantlets
cv. Ney Poovan (AB) during primary and secondary hardening stages. Among the bacterial endophytes, B. amyloliquefaciens was found to significantly enhance plant height, leaf production, root numbers and root length compared to untreated control. Activity of defense enzymes were also enhanced and such increase in activity was observed to be to an extent of 93.67% in peroxidase, 92.39% polyphenol oxidase, 97.60% phenylalanine ammonia lyase and 26.23% in β-1, 3-glucanase defence enzymes in plants biohardened with B. amyloliquefaciens (VB7) over untreated control after inoculation of Foc. Tissue cultured plants of Ney Poovan biohardened with B. amyloliquefaciens (VB7), B. paraconglomeratum (YEB PT2) and S. maltophilia (YEB RH2) were completely free from wilt incidence symptoms upto planting stage when challenged with Foc inoculum under pot culture conditions. As among these three endophytes, B. amyloliquefaciens (VB7) also influenced favourable growth promotion, it can serve as a potential biocontrol agent for management of Fusarium wilt of banana.
Keywords: Fusarium wilt, banana, bacterial endophytes, biohardening