Abstract
Fungicides among agrochemicals are consistently used in high throughput agricultural practices to protect plants from damaging impact of phytopathogens and hence to optimize crop production. However, the negative impact of fungicides on composition and functions of soil microbiota, plants and via food chain, on human health is a matter of grave concern. Considering such agrochemical threats, the present study was undertaken to know that how fungicide-tolerant symbiotic bacterium, Mesorhizobium ciceri affects the Cicer arietinum crop while growing in kitazin (KITZ) stressed soils under greenhouse conditions. Both in vitro and soil systems, KITZ imparted deleterious impacts on C. arietinum as a function of dose. The three-time more of normal rate of KITZ dose detrimentally but maximally reduced the germination efficiency, vigor index, dry matter production, symbiotic features, leaf pigments and seed attributes of C. arietinum. KITZ-induced morphological alterations in root tips, oxidative damage and cell death in root cells of C. arietinum were visible under scanning electron microscope (SEM). M. ciceri tolerated up to 2400 µg mL−1 of KITZ, synthesized considerable amounts of bioactive molecules including indole-3-acetic-acid (IAA), 1-aminocyclopropane 1-carboxylate (ACC) deaminase, siderophores, exopolysaccharides (EPS), hydrogen cyanide, ammonia, and solubilised inorganic phosphate even in fungicide-stressed media. Following application to soil, M. ciceri improved performance of C. arietinum and enhanced dry biomass production, yield, symbiosis and leaf pigments even in a fungicide-polluted environment. At 96 µg KITZ kg−1 soil, M. ciceri maximally and significantly (p ≤ 0.05) augmented the length of plants by 41%, total dry matter by 18%, carotenoid content by 9%, LHb content by 21%, root N by 9%, shoot P by 11% and pod yield by 15% over control plants. Additionally, the nodule bacterium M. ciceri efficiently colonized the plant rhizosphere/rhizoplane and considerably decreased the levels of stressor molecules (proline and malondialdehyde) and antioxidant defence enzymes viz. ascorbate peroxidise (APX), guaiacol peroxidise (GPX), catalase (CAT) and peroxidises (POD) of C. arietinum plants when inoculated in soil. The symbiotic strain effectively colonized the plant rhizosphere/rhizoplane. Conclusively, the ability to endure higher fungicide concentrations, capacity to secrete plant growth modulators even under fungicide pressure, and inherent features to lower the level of proline and plant defence enzymes makes this M. ciceri as a superb choice for augmenting the safe production of C. arietinum even under fungicide-contaminated soils.
Highlights
Cicer arietinum L. crops often suffers from the attack of phytopathogens, which damage the crop and limits its yield
These results indicate that lower fungicide concentrations resulted in maximum tolerance index (TI), whereas the 3 × dose exhibited the minimum TI in C. arietinum
Fungicide applied in the study detrimentally affected the germinative ability of C. arietinum leading to the decrease in plant growth parameters as recorded both under in vitro and soil system
Summary
Cicer arietinum L. (chickpea) crops often suffers from the attack of phytopathogens, which damage the crop and limits its yield. The fungicide pyrimorph was found to strongly inhibit the electron transport (ET) reactions of chloroplasts and adversely affected the physiology of whole p lants[14] To overcome these problems, certain physico-chemical approaches have been used to limit or destroy the toxic effects of pesticides. The technique, which relies on the use of soil microbiota, often referred to as ‘microbial remediation’ is gaining impetus to convert contaminants to simpler and harmless forms and to mitigate the pesticide pollution To this end, scientists have identified pesticide degrading/detoxifying microbes endowed with potential plant growth promoting activities. Given the nutritive importance of C. arietinum in the global dietary systems, the negative impact of fungicides on legume production, the lack of adequate information on fungicidal response to C. arietinum and the inherent bioremediation potential of PGPR, this study was formulated to explore the following: (i) the fungicidal toxicity to C. arietinum both under in vitro bioassays and in pot-house conditions (ii) the kitazin-induced distortion, oxidative damage and cell death in C. arietinum root cells (iii) to identify fungicide tolerant symbiotic bacterium from chickpea nodules (iv) to determine the production of bioactive molecules under fungicide stress (v) to evaluate the effects of M. ciceri on physiological and biochemical attributes of C. arietinum (vii) to determine the impact of stressor molecules on antioxidant enzymes of C. arietinum foliage detached from fungicide-treated and Mesorhizobium-inoculated chickpea and (viii) to evaluate the rhizosphere/rhizoplane colonization efficiency/ competence ofnodule bacterium
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
