Improved photosystem II and defense enzymes activity in rice (Oryza sativa) by biopriming against Xanthomonas oryzae pv. oryzae

Abstract

Bacterial blight (BB), caused by Xanthomonas oryzae pv. oryzae (Xoo) is a major threat to rice production as it accounts for loss up to 50% of annual rice grain yield. Xoo causes leaf tissue necrosis and as a result there is downregulation of the photosynthetic mechanisms of plant. Measurement of chl a fluorescence is an easy, fast, non-invasive and highly sensitive technique that can be used to understand plant health by measuring alterations in PSII activity, in response to different biotic and abiotic stresses. In the present investigation, rice seeds were bio-primed with two bacterial spp. (e.g. Bacillus subtilis and B. megaterium) and one fungal strain (i.e. Trichoderma erinaceum). The induction of defence against BB disease by bio-priming with biotic agents, was studied as response in alteration of PSII and defence enzymes activity. Field experiment was conducted with the best biotic agent; i.e. B. subtilis obtained from all experiments to study whether defence induction by it have any side effect on rice yield and biomass. Net house and field experiments have suggested that among all the biotic agents studied, bio-priming of rice seeds with B. subtilis has protected the photosynthetic machinery of plants from being damaged by BB without having any detrimental effect on rice grain yield.

Seed Bio-priming of wheat with a novel bacterial strain to modulate drought stress in Daegu, South Korea

“…Seed biopriming, a defense mechanism that protects the seeds when they are competing in unfavorable conditions, improves the germination capacity of plants. In addition, seed biopriming improves the energy status of the mitochondria and enhances protein synthesis, which also leads to improved germination ( Sukanya et al., 2018 ; Samal et al., 2020 ; Negi and Bharat, 2021 ). Owing to the significance of the seed vigor index, germination potential, and growth rate index, PEG concentrations of over 10% did not improve plant drought tolerance in vitro .…”

Seed biopriming as a promising approach for stress tolerance and enhancement of crop productivity: a review

“…Seed priming resulted in a 20% decrease in disease incidence in chili (Capsicum annuum L.) through aggregation of phenolic compounds and enhanced activities of antioxidant enzymes such as peroxidase, phenylalanine ammonia lyase, chitinase, lipoxygenase and polyphenol oxidase. 81 83 Song et al 84 primed pepper (C. annuum L.) and cucumber (C. sativus L.) seeds with heat stable metabolites prepared from Bacillus gaemokensis. These metabolites identified as leucine-proline cyclodipeptide, decreased disease incidence under controlled and field conditions.…”

“…found that biopriming with P. aeruginosa induced the accumulation of natural antioxidants, enzymes and defence‐associated biomolecules in R. solani infected maize ( Z. mays L.) plants. Moreover, B. subtilis biopriming protected the photosynthetic machinery of rice ( O. sativa L.) infested with bacterial blight causing Xanthomonas oryzae by altering photosystem II and defence activities in plants 83 . Song et al 84 .…”