Seed Biopriming With Trichoderma Strains Isolated From Tree Bark Improves Plant Growth, Antioxidative Defense System in Rice and Enhance Straw Degradation Capacity

Abstract

This study is a unique report of the utilization of Trichoderma strains collected from even tree barks for rice plant growth, its health management, and paddy straw degradation. Seven different spp. of Trichoderma were characterized according to morphological and molecular tools. Two of the isolated strains, namely Trichoderma hebeiensis and Trichoderma erinaceum, outperformed the other strains. Both of the strains controlled four important rice pathogens, i.e., Rhizoctonia solani (100%), Sclerotium oryzae (84.17%), Sclerotium rolfsii (66.67%), and Sclerotium delphinii (76.25%). Seed bio-priming with respective Trichoderma strains reduced the mean germination time, enhanced the seedling vigor and total chlorophyll content which could be related to the higher yield observed in two rice varieties; Annapurna and Satabdi. All the seven strains accelerated the decomposition of rice straw by producing higher straw degrading enzymes like total cellulase (0.97–2.59 IU/mL), endoglucanase (0.53–0.75 IU/mL), xylanase (145.35–201.35 nkat/mL), and laccase (2.48–12.60 IU/mL). They also produced higher quantities of indole acetic acid (19.19–46.28 μg/mL), soluble phosphate (297.49–435.42 μg/mL), and prussic acid (0.01–0.37 μg/mL) which are responsible for plant growth promotion and the inhibition of rice pathogen populations. Higher expression of defense enzymes like catalase (≥250% both in shoot and root), peroxidase (≥150% in root and ≥100% in shoot), superoxide dismutase (≥ 150% in root and ≥100% in shoot), polyphenol oxidase (≥160% in shoot and ≥120% in shoot), and total phenolics (≥200% in root and ≥250% in shoot) as compared to the control indicates stress tolerance ability to rice crop. The expression of the aforementioned enzymes were confirmed by the expression of corresponding defense genes like PAL (>3-fold), DEFENSIN (>1-fold), POX (>1.5-fold), LOX (>1-fold), and PR-3 (>2-fold) as compared to the non-treated control plants. This investigation demonstrates that Trichoderma strains obtained from tree bark could be considered to be utilized for the sustainable health management of rice crop.

Modulation of plant growth and antioxidative defense system through endophyte biopriming in cotton (Gossypium spp.) and non-host crops

“…In another study, fourteen endophytes were tested for their efficacy on seed germination in rice and it was found that, Penicillium citrinum showed maximum seed germination, whereas seeds treated with Cladosporium cladosporioides exhibited highest shoot length ( Lalngaihawmi et al., 2018 ). In a recent report, biopriming with Trichoderma strains reduced the mean germination time, increased the seedling vigor and chlorophyll content in two rice varieties ( Swain et al., 2021 ). Therefore, biopriming with endophytes, not only antagonists like Trichoderma , has proven to be a better tool in enhancing the germination in many crops like rice, maize and now in cotton through the findings of this experiment ( Figure 2 ).…”

“…On the contrary, seed biopriming studies are mostly limited to popular biocontrol agents such as Trichoderma viride , T . harzianum and Pseudomonas fluorescens being used for biopriming in many of the crops ( Aamir et al., 2019 ; Ferrigo et al., 2019 ; Singh et al., 2020a ; Swain et al., 2021 ).…”

“…Endophyte mediated induction of disease resistance has been observed to be systemic in nature. Swain et al. (2021) reported that seed biopriming with Trichoderma strains reduced mean germination time, enhanced the seedling vigor and total chlorophyll content.…”

Unlocking PGPR-Mediated Abiotic Stress Tolerance: What Lies Beneath

“…Similarly, several ACC-deaminase-possessing strains have been found to efficiently enhance stress tolerance of tomato and pepper (Mayak et al, 2004), or wheat (Chandra et al, 2020), under water-deficient conditions (Table 1). The putative priming effect of such strains may be related to enhanced catalase, ascorbate peroxidase or glutathione peroxidase activity in inoculated plants (Mellidou et al, 2021;Swain et al, 2021). By contrast, in some other studies, PGPR inoculation resulted to suppressed expression of stress-responsive genes or genes encoding ROS-scavenging enzymes involved in the protection of plant upon stress application (Goswami and Deka, 2020).…”

Screening, Isolation and Characterization of Heat Stress Tolerant Trichoderma Isolates: Sustainable Alternative to Climate Change

“…Similarly siderophore, HCN, chitinase and protease production were observed higher on petriplates and vials inoculated with BHU P4 at both room temperature and stressed conditions. Various studies have reported the production of these hydrolytic enzymes by biocontrol agents having crucial role in plant growth promotion and defense mechanism (Aamir et al, 2019;Baiyee et al, 2019;Swain et al, 2021). Siderophore production enhances the uptake of micronutrients such as Fe, Zn, Cu, etc.…”