Acuities into tolerance mechanisms via different bioassay during Brassicaceae-Alternaria brassicicola interaction and its impact on yield

Abstract

Heavy losses by dark leaf spot disease in oilseed Brassica have incited research towards identifying sources of genetic tolerance against causal pathogen, Alternaria brassicicola. Several morpho-molecular parameters were evaluated to test the performance of field mustard and rapeseed genotypes under artificial inoculation with this pathogen. During Brassica-Alternaria interaction, physio-biochemical defense response was witnessed in tolerant genotypes. Two tolerant genotypes (one for field mustard and one for rapeseed), i.e., EC250407 and EC1494 were identified. However, necrotic lesions were more prominent in susceptible genotypes with minimum chlorophyll (chlorophyll a, chlorophyll b and total chlorophyll) and carotenoids contents. Contrary to photosynthetic pigments, increase in total soluble protein (TSP) contents was observed with disease progression in susceptible genotypes. Tolerant genotypes of field mustard and rapeseed displayed remarkable increase in the activities of redox enzyme in infected leaves with least yield loss (6.47% and 5.74%) and disease severity index (DSI) of 2.9 and 2.1, respectively. However, yield/plant showed close association with other morpho-yield parameters, photosynthetic pigments and redox enzymes (superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD)) activities except silique length and TSP. Based on the results of morpho-biochemical analyses, redox enzymes and morphological parameters; their interplay is proposed to determine the tolerance outcome of the Brassica-A. brassicicola interaction.

The Effect of Photoperiod on Necrosis Development, Photosynthetic Efficiency and ‘Green Islands’ Formation in Brassica juncea Infected with Alternaria brassicicola

“…A similar trend of a decreased chlorophyll content has been described during progressive infection of B. oleracea with A. brassicicola [35] and B. juncea infected with A. brassicae [48]. Chlorophyll content decreased in tolerant and susceptible B. napus and B. rapa cultivars to A. brassicicola infection with much stronger degradation in susceptible cultivars [49]. Lowered chl a level accompanied by an extensive production of ROS has been also described in susceptible B. napus infected with Leptosphaeria maculans, which induces yellowish necrotic spots [50].…”

“…Carotenoids along with chlorophylls are important photosynthetic pigments that are components of photosystems, they absorb an excess of light, and play a role in photoprotection [51]. In tolerant and susceptible B. napus and B. rapa cultivars, a decrease in the carotenoid levels in response to A. brassicicola has been noted [49]. However, an increase in carotenoid content has been described in resistant B. napus cultivars infected with L. maculans, while in susceptible oilseed cultivars the carotenoid levels decreased [50].…”

Alternaria brassicicola‐induced ROS accumulation during black spot disease differentially affects antioxidant efficiency, phenolic content and susceptibility of Brassica species

“…Contrary to these results, Munir et al. (2020) have described a much higher increase in the CAT activity of B . napus and B .…”

The Effect of Banana Rhizosphere Chemotaxis and Chemoattractants on Bacillus velezensis LG14-3 Root Colonization and Suppression of Banana Fusarium Wilt Disease

“…The results of this study demonstrated that Bacillus velezensis LG14-3 was chemotactic to banana root exudates and that citric acid and glycine in root exudates enhanced the abilities of LG14-3 root colonization and pathogen inhibition. Sustaining chlorophyll content in plants upon pathogen invasion is vital, as it will permit plant cells to continue photosynthesis [54]. Moreover, pot experiments showed that LG14-3 was efficient in increasing the chlorophyll a and chlorophyll b contents of bananas, which may be one of the reasons for the increase in plant height and weight after the LG14-3 application.…”