Seed biopriming with drought tolerant isolates ofTrichoderma harzianumpromote growth and drought tolerance inTriticum aestivum

Abstract

Green house study was aimed to investigate the effect of seed biopriming with drought tolerant isolates of Trichoderma harzianum, viz. Th 56, 69, 75, 82 and 89 on growth of wheat under drought stress and to explore the mechanism underlying plant water stress resilience in response to Trichoderma inoculation. Measurements of relative water content, osmotic potential, osmotic adjustment, leaf gas exchange, chlorophyll fluorescence and membrane stability index were performed. In addition, analysis of the phenolics, proline, lipid peroxidation and measurements of phenylalanine ammonia-lyase activity were carried out. Seed biopriming enhanced drought tolerance of wheat as drought induced changes like stomatal conductance, net photosynthesis and chlorophyll fluorescence were delayed. Drought stress from 4 to 13 days of withholding water induced an increase in the concentration of stress induced metabolites in leaves, while Trichoderma colonisation caused decrease in proline, malondialdehyde (MDA) and hydrogen peroxide (H 2 O 2 ), and an increase in total phenolics. A common factor that negatively affects plants under drought stress conditions is accumulation of toxic reactive oxygen species (ROS), and we tested the hypothesis that seed biopriming reduced damages resulting from accumulation of ROS in stressed plants. The enhanced redox state of colonised plants could be explained by higher L-phenylalanine ammonia-lyase (PAL) activity in leaves after 13 days of drought stress in Trichoderma treated plants. Similar activity was induced in untreated plants in response to drought stress but to a lower extent in comparison to treated plants. Our results support the hypothesis that seed biopriming in wheat with drought tolerant T. harzianum strains increased root vigour besides performing the process of osmoregulation. It ameliorates drought stress by inducing physiological protection in plants against oxidative damage, due to enhanced capacity to scavenge ROS and increased level of PAL, a mechanism that is expected to augment tolerance to abiotic stresses.

Legume endosymbionts: Drought stress tolerance in second‐generation chickpea (Cicer arietinum) seeds

“…However, the mechanism of action remains unclear. Our results agree with an earlier study by Shukla, Awasthi, Rawat, and Kumar () who reported endophyte Trichoderma harzianum treated wheat F 1 plants produced less (13%–27%) H 2 O 2 compared to untreated (60%) wheat plants under drought stress. To the best of our knowledge, this is the first study to address this question in F2 chickpeas.…”

Influence of Field Soil Drought Stress on Some Key Physiological, Yield and Quality Traits of Selected Newly-Developed Hexaploid Bread Wheat (Triticum aestivum L.) Cultivars

“…The differential response of the different wheat cultivars to drought or normal irrigation conditions might have been due to their differential genetic potential to the prevalent conditions. Previous studies have shown that severe water stress from seedling to maturity reduced gas exchange activities and grain yield components in wheat, especially photosynthesis, stomatal conductance, productive tillers per unit area, number of grains per spike and 1000-grain weight (Ahmed et al 2007;Kilic & Yagbasanlar 2010;Nouri-Ganbalani et al 2009;Shukla et al 2015). However, it is shown that among the cultivars, Faisalabad-2008 maintained its superior performance and produced maximum yield under drought conditions.…”

“…This might have showed that drought stress has a direct impact on the photosynthetic activities by disrupting all major components due to stomatal closure that reduced CO 2 uptake under drought conditions. Early reports of photosynthesis include carbon reduction cycle, thylakoid electron transport, stomatal control of the CO 2 supply and disturbance of water balance (Shukla et al 2015;Vandoorne et al 2012). In fluctuating environmental conditions or environmental stress, stomatal and photosynthetic responses of plants differ especially under changing light and temperature conditions which lag in stomatal behavior and limit photosynthetic activity (Lawson et al 2011;Lawson & Blatt 2014).…”

Effect of Isoproturon With and Without Adjuvants on Photosynthetic Attributes of Wheat and Its Associated Weeds

“…This might be due to stomotal closure at early stage of herbicide spray that reduced CO 2 uptake under herbicide application. Early reports revealed that herbicides has a direct impact on photosynthetic activity by disrupting all major components of photosynthesis including carbon reduction cycle, thylakoid electron transport, stomatal control of the CO 2 supply and cholorophyll activity (Naseer-ud-Din et al, 2011;Vandoorne et al, 2012;Shukla et al, 2015). Different post-emergence herbicides has been used to control weeds but it is documented that application of post-emergence herbicide with adjuvants was found to be more effective in controlling the weeds (Naseer-ud-Din et al, 2011).…”