Efficacy of indigenous plant growth-promoting rhizobacteria and Trichoderma strains in eliciting resistance against bacterial wilt in a tomato

Abstract

Bacterial wilt of tomato caused by Ralstonia solanacearum is a serious threat to tomato production worldwide. For eco-friendly management of bacterial wilt of tomato, the rhizospheric microorganisms belonging to the genera Bacillus (6 isolates), Brevibacillus (1 isolate), Pseudomonas (3 isolates), and Trichoderma (8 isolates) were studied for their ability to induce innate immunity in tomato, individually and in combination against R. solanacearum in greenhouse and field studies. In laboratory studies, maximum germination percent of 93%, vigor index of 1609 was noted in seed bacterization with P. fluorescens Pf3, followed by 91% germination, vigor index of 1593 in treatment with T. asperellum T8 over control. Under greenhouse conditions, protection against bacterial wilt in individual treatments with PGPRs ranged from 38 to 43% and Trichoderma sp. ranged from 39 to 43% in comparison to control. In comparison to individual seed treatment, among different combinations, maximum seed germination percent of 97% was recorded with combination P. fluorescens Pf3 + T. longibrachiatumUNS11. In greenhouse studies' combination seed treatment with P. fluorescens Pf3 + T. longibrachiatumUNS11 offered an impressive 62% protection against bacterial wilt over control. Similarly, under field conditions, seed treatment with P. fluorescens Pf3 + T. longibrachiatumUNS11 resulted in 61% protection. The innate immunity triggered by eco-friendly seed treatment was analyzed by expression to defense-related enzymes such as peroxidase, phenylalanine ammonialyase, and polyphenol oxidase in comparison to control. This study indicated that the potential benefits of using combination treatments of beneficial microorganisms in effectively inducing resistance are possible for dual benefits of enhanced plant growth, tomato yield, and pathogen suppression.

Inhibitory Effect of Trichoderma asperellum Isolate against Ralstonia solanacearum Causing Brinjal Wilt

“…Inoculation of T. asperellum Tc-Jjr-02 at six hours before and after and simultaneously with pathogens provided protection (reducing the symptom index by 56-63%) for young tobacco plants against tobacco bacterial wilt disease caused by R. solanacearum (Jalaluddin et al, 2021). Previous studies (Konappa et al, 2020, Konappa et al, 2018, Mohamed et al, 2020 also revealed a reduction of potato and tomato wilt, caused by Ralstonia solanacearum (Smith) by T. asperellum isolate under greenhouse and field conditions. Even leaf spray of T. asperellum also reduced the growth of bacterial spots on tomato caused by Xanthomonas (Chien and Huang, 2020).…”

“…Even leaf spray of T. asperellum also reduced the growth of bacterial spots on tomato caused by Xanthomonas (Chien and Huang, 2020). In addition to disease reduction, T. asperellum also enhanced tomato seed germination, fruit yield, plant growth and increased the dry weight of plant biomass promotion under field conditions (Konappa et al, 2020, Jalaluddin et al, 2021.…”

Reproduction of a living collection of dendrological garden plants for urban landscaping

“…In Mirikaria, the best preparation affecting the increase in the diameter of the root neck was Black yeast: 5.6; 6.6; 8.8; 9.1 mm (Fig. 6,7,8,9).…”

“…These are primarily antibiotics with a pronounced fungicidal effect, which inhibit the development of many pathogens and inhibit their reproductive capacity. The use of these microscopic fungi has given positive results in various agricultural crops due to their high antagonistic ability [7][8][9]. The use of yeast as plant growth promoting agents is underutilized.…”

Biological Seed Treatments

“…Many other fungi and bacteria are endophytic and can potentially be used for seed treatment. These include fungi in the genera Trichoderma (Harman 2011;Woo et al 2014;Doni et al 2017), Aspergillus (Ismail et al 2020), Penicillium (Ikram et al 2018a), Clonostachys (Shafia et al 2001), Piriformaspora (Sherameti et al 2005), and Yarrowia lipolutoca (Franza et al 2019), as well as bacteria in the genera Pseudomonas (Konappa et al 2020) and Bacillus (Konappa et al 2020;Brannen 1997), and in the family Rhizobiacae (Chi et al 2015).…”