Development of transgenic tomato resistant to early blight & Chilli for anthracnose (Ongoing)
To improve the regeneration and transformation system in chilli cv G-4
Generation of putative transformants in tomato cv Arka Vikas, Chilli cv G-4 through Agrobacterium mediated transformation with chitinase gene
Molecular analysis of transformants
Contained establishment and screening the transformants for disease resistance
Dr J.B. MYTHILI
Dr M. Manamohan
Dr Girija Ganeshan
Dr P. Chowdappa
Dr A. Sadashiva
Dr K. Madhavi Reddy
Four genes viz., chitinase gene from bio-control gent viz., Trichoderma harzianum and Metarhizium anisopliae, polygalacturonase inhibitor protein (PGIP) a hydrolytic enzyme involved in fungal inhibition from chilli and NPRI a key gene involved in regulation of plant disease resistance have been cloned. All these genes have been put under expression cassettes under the control of CaMV 35S promoter and mobilized into binary vector for expression in plants for enhanced fungal resistance.
The advanced stabilized transgenic line with Trichoderma harzianum chitinase gene in T3 generation expressed 60% tolerance to Alternaria solani at the seedling stage in response to control plants while for two consecutive (T3 and T4) generations at fully grown stage, the transgenic plants recorded intermediate response with PDI of less than 50% while the control Arka Vikas recorded greater than 60% PDI. Transgenic lines also showed significantly reduced lesion size compared to control in the in vitro leaf bio-assy. The delayed development of disease ( about 10days) and reduced disease development can help in effective disease management and thereby reduce yield losses of the crop and reduced use of chemical pesticides can be expected.
With the objective of obtaining resistance against Alternaria solani co-transforamation approach using Chitinase and PGIP genes in two Agrobacterium cultures was standardized and co-transformants with both chitinase and PGIP genes were obtained. This results suggest that this approach can be used for pyramiding tomato with two or more genes for enhanced fungal resistance.
Problems associated with the low rate of conversion of shoot buds to elongated shoots as well as inhibition of rooting during optimization of regeneration protocol for chilli were addressed.