Climate change is an invisible, silent killer with calamitous effects on living organisms. As the sessile organism, plants experience a diverse array of abiotic stresses during ontogenesis. The relentless climatic changes amplify the intensity and duration of stresses, making plants dwindle to survive. Plants convert 1–2% of consumed oxygen into reactive oxygen species (ROS), in particular, singlet oxygen (¹O₂), superoxide radical (O₂^•–), hydrogen peroxide (H₂O₂), hydroxyl radical (^•OH), etc. as a byproduct of aerobic metabolism in different cell organelles such as chloroplast, mitochondria, etc. The regulatory network comprising enzymatic and non-enzymatic antioxidant systems tends to keep the magnitude of ROS within plant cells to a non-damaging level. However, under stress conditions, the production rate of ROS increases exponentially, exceeding the potential of antioxidant scavengers instigating oxidative burst, which affects biomolecules and disturbs cellular redox homeostasis. ROS are similar to a double-edged sword; and, when present below the threshold level, mediate redox signaling pathways that actuate plant growth, development, and acclimatization against stresses. The production of ROS in plant cells displays both detrimental and beneficial effects. However, exact pathways of ROS mediated stress alleviation are yet to be fully elucidated. Therefore, the review deposits information about the status of known sites of production, signaling mechanisms/pathways, effects, and management of ROS within plant cells under stress. In addition, the role played by advancement in modern techniques such as molecular priming, systems biology, phenomics, and crop modeling in preventing oxidative stress, as well as diverting ROS into signaling pathways has been canvassed.

Biopesticides are revolutionary crop protectants that protect crops from vast array of pests and pathogens in eco-friendly manner. They show plethora of benefits over synthetic pesticides, such as target specificity, less toxicity and biodegradability; however, they lack position in crop protection market and represent only 3.5% of global pesticides market (Olson et al., 2013). Though biopesticides lag behind in commercial pesticide market, they have great deals to offer for development of sustainable agriculture. The successful market for biopesticides can be achieved through understanding the major challenges and constraints faced by them and developing new strategies such as optimising delivery system; screening new and better strains; educating farmers and others to cope up with encountering hurdles.

The native strains of Trichoderma and Rhizobacteria were isolated from rhizosphere of seven different crops from agroecosystem of peri-urban area of Lucknow, Uttar Pradesh, (India). The five isolates Trichoderma lixii TvR1, T. brevicompactum TbS2, Bacillus subtilis BS6, B. subtilis CS13 and Pseudomonas aeruginosa Tr20 displayed positive antagonistic potential against Fusarium oxysporum f. sp. lycopersici (Fol) and Alternaria solani under in vitro conditions. The biocontrol agents (BCAs) were found to produce cell wall degrading enzymes (CWDEs) including, chitinase, protease and cellulase. T. lixii TvR1 and P. aeruginosa Tr20 were found to be the most effective strains that showed significant inhibitory effect on pathogens. Dual culture, volatile metabolite and culture filtrate assay revealed percentage radial inhibition of Fol (55.31%, 54.09%; 22.24%, 10.06% and 67.85%, 51.38%) and A. solani (66.54%, 61.54%; 20.76%, 27.6% and 41.74%, 38.52%) by T. lixii TvR1 and P. aeruginosa Tr20, respectively. Antagonistic assays revealed probable involvement of mechanism of mycoparasitism and production of secondary metabolites such as antibiotics by both biocontrol agents. In addition to biocontrol activity, the BCAs displayed plant growth promoting (PGP) activities such as production of indole acetic acid (IAA), siderophores and ammonia and phosphate solubilisation.

The incidence of biotic perturbation in plants has been amplified due to increased resistance and the resurgence of pathogens. To mitigate stress and promote food production, agrochemicals are being used boundlessly and they have augmented the problem of disease re-occurrence and agroecosystem degradation. With the perception of urgency to reduce biotic stress sustainably, the present study was undertaken. Four native rhizospheric microbes: Trichoderma lixii, T. brevicompactum and two strains of Bacillus subtilis, were evaluated for their antagonistic potential toward soil-borne and foliar pathogens of tomato under pot conditions. The data obtained revealed T. lixii as the most effective isolate, which substantially reduced the disease severity and promoted plant growth. In two consecutive pot experiments, T. lixii was observed to reduce the fusarium wilt and early blight severity by 32% and 31%; and 30% and 25%, respectively, compared to the untreated control. Moreover, T. lixii was reported to colonize the plant roots, which was evident from the result obtained for biofilm formation and spores colonization on root cells. TvR1 also improved the photosynthetic content of both infected and non-infected plants. The conclusion drawn from the result suggested that the native microbial rhizospheric isolate T. lixii was effective in ameliorating the biotic stress, which might be due to root colonizing ability, and therefore, it could be designed into a bioinoculant for green agriculture.