1CSIR-National Botanical Research Institute, Rana Pratap Marg, Lucknow-226 001, Uttar Pradesh, India
2Academy of Scientific and Innovative Research, Ghaziabad-201 002, Uttar Pradesh, India
3State Planning Commission, Lucknow-226 001, Uttar Pradesh, India
*Corresponding Author: H.K. Yadav, CSIR-National Botanical Research Institute, Rana Pratap Marg, Lucknow-226 001, Uttar Pradesh, India, Email: h.yadav@nbri.res.in
Online Published on 30 March, 2026.
Leaf blight caused by Alternaria spp. is one of the serious concerns in guar production worldwide. Despite this, the interaction of host-pathogen and responses of different guar genotypes against necrotrophic fungus Alternaria is still not much explored.
In the present investigation, six guar genotypes have been infected with Alternaria and observed differential responses by using various parameters, including biochemical assays, antioxidant activities (SOD, CAT, PO, GPx, APx PAL, β-1,3-glucanase enzyme, total phenolic content) and physiological parameters (chlorophyll content, carotenoid and photosynthetic yield-II).
After the pathogenicity of Alternaria there was a substantial shift in the biochemical activity in all the inoculated resistant genotypes compared to their respective controls. Moreover, a significant reduction was also observed up to 65% in terms of physiological performance, such as total chlorophyll content, carotenoids and photosynthetic yield-II content, after 14 days of pathogenicity. The genotypes RGC-1066 and RGC-936 showed relatively more resistance and RGC-936 showed relatively more susceptibility towards Alternaria infection. These findings also imply that host-pathogen interactions factors have a role in the differential expression of defence-related enzymes and antioxidant activities in response to Alternaria inoculation.
Alternaria alternata, Alternaria leaf blight, Defence-related enzymes, Differential response, Guar
