A combined transcriptional, biochemical and histopathological study unravels the complexity of Alternaria resistance and susceptibility in Brassica coenospecies

In this study, we have selected B. juncea (susceptible), Sinapis alba (moderately tolerant) and Camelina sativa (highly resistant) as a source for understanding and unraveling the mechanism of disease resistance against A. brassicae. Histopathological studies showed early onset of necrosis in B. juncea (1day post inoculation) and delayed in S. alba (2 dpi) and C. sativa (3 dpi) respectively. Based on the biochemical observations, early and enhanced production of hydrogen peroxide (H2O2) was observed in C. sativa and S. alba (6 hpi) when compared to B. juncea (12 hpi) after A. brassicae infection. An increase in catalase activity was observed in both C. sativa (36% at 6 hpi) and S. alba (15% at 12 hpi), whereas it significantly decreased in B. juncea at 6 hpi (23 %), 12hpi (30 %) and 24 hpi (8 %), which might be involved for improving disease resistance to A. brassicae in C. sativa and S. alba. However, little change in peroxidase activity was observed in C. sativa compared to S. alba and B. juncea. Furthermore, to study the defense response of C. sativa, S. alba and B. juncea against A. brassicae gene expression analysis of jasmonic acid (PR-3, PR-12) and salicylic acid (PR-1, PR-2) responsive genes were studied using qRT-PCR. Based on the results, only PR-3 and PR-12 expression was significantly induced in C. sativa and S. alba when compared to B. juncea after Alternaria challenge suggesting their vital role for Alternaria resistance in C. sativa and S. alba. In contrast, SA...
Source: Fungal Biology - Category: Biology Source Type: research