Role of Trichoderma harzianum in mitigating NaCl stress in Indian mustard (Brassica juncea L) through antioxidative defense system

Abstract

Salinity stress affected crop production of more than 20% of irrigated land globally. In the present study the effect of different concentrations of NaCl (0, 100, and 200 mM) on growth, physio-biochemical attributes, antioxidant enzymes, oil content, etc. in Brassica juncea and the protective role of Trichoderma harzianum (TH) was investigated. Salinity stress deteriorates growth, physio-biochemical attributes, that ultimately leads to decreased biomass yield in mustard seedlings. Higher concentration of NaCl (200 mM) decreased the plant height by 33.7%, root length by 29.7% and plant dry weight (DW) by 34.5%. On the other hand, supplementation of TH to NaCl treated mustard seedlings showed elevation by 13.8, 11.8, and 16.7% in shoot, root length and plant DW respectively as compared to plants treated with NaCl (200 mM) alone. Oil content was drastically affected by NaCl treatment; however, TH added plants showed enhanced oil percentage from 19.4 to 23.4% in the present study. NaCl also degenerate the pigment content and the maximum drop of 52.0% was recorded in Chl. ‘a’. Enhanced pigment content was observed by the application of TH to NaCl treated plants. Proline content showed increase by NaCl stress and maximum accumulation of 59.12% was recorded at 200 mM NaCl. Further enhancement to 70.37% in proline content was recorded by supplementation of TH. NaCl stress (200 mM) affirms the increase in H2O2 by 69.5% and MDA by 36.5%, but reduction in the accumulation is recorded by addition of TH to mustard seedlings. 200 mM NaCl elevated SOD, POD, APX, GR, GST, GPX, GSH, and GSSG in the present study. Further enhancement was observed by the application of TH to the NaCl fed seedlings. NaCl stress suppresses the uptake of important elements in both roots and shoots, however, addition of TH restored the elemental uptake in the present study. Mustard seedlings treated with NaCl and TH showed restricted Na uptake as compared to seedlings treated with NaCl alone. In conclusion, TH proved to be very beneficial in imparting resistance to the mustard plants against NaCl stress through improved uptake of essential elements, modulation of osmolytes and antioxidants.

Physiological responses of crop plants against Trichoderma harzianum in saline environment

“…are important physiological strategy for coping with the consequences of abiotic stress and maintaining ion homeostasis (Sairam et al 2002, Siddiqui and Khan 2011, Rasool et al 2013. Further it was observed that a Trichoderma inoculation enhanced antioxidant enzyme activities and decreased salt stress in plants (Hajiboland et al 2010, Ahmad et al 2015.…”

“…It was reported that the application of Th in a saline habitat improved biomass and growth parameters (Moud and Maghsoudi 2008, Rasool et al 2013, Ahmad et al 2014. The increase in growth relative water content and biomass production with a Th application may be due to its ability to produce phytohormones like gibberellins and cytokine, which may not only promote the plant growth but also increase some degree of tolerance in a saline environment (Harman 2000, Benitez et al 2004, Iqbal and Ashraf 2013, Ahmad et al 2015.…”

Zinc application mitigates the adverse effects of NaCl stress on mustard [Brassica juncea (L.) Czern & Coss] through modulating compatible organic solutes, antioxidant enzymes, and flavonoid content

“…The accumulation of H 2 O 2 in salt-stressed plants may be due to reduced RWC, which limits H 2 O 2 diffusion from its generation site (Weisany et al 2014). Stressmediated H 2 O 2 production, subsequent membrane leakage, and MDA formation in combination determine the intensity of oxidative stress (Tavallali et al 2009;Ahmad et al 2014Ahmad et al , 2015a. Loss of membrane integrity from increased ROS production causes leakage of important mineral ions from cellular organelles (Tuna et al 2007).…”

“…Increased proline accumulation is believed to maintain tissue water potential under environmental stresses, thus offering an important tolerance strategy (Ahanger et al 2014(Ahanger et al , 2015Ahmad et al 2015aAhmad et al , 2015b. Saltstressed plants maintain higher proline content through enhancing the activity of key enzymes involved in proline synthesis .…”

Mitigation of sodium chloride toxicity inSolanum lycopersicumL. by supplementation of jasmonic acid and nitric oxide

“…Salinity stress is considered as one of the most severe abiotic stresses that hamper the normal growth and development of plants (Ahmad et al 2015;. Salinity stress is increasing consistently at an alarming rate worldwide, leading to reduced fertility of land, especially in arid and semiarid regions.…”