Selecting Trichoderma and Pseudomonas species from pigeonpea rhizosphere microbial complex and profiling potential candidates for management of

Abstract

Pigeonpea wilt, caused by the soil‐inhabiting Fusarium udum , is a severe threat to crop production, attributed to its aetiology and sustainable management. Host plant resistance is the only deployable practice under agricultural sustainability whose durability can be achieved through the application of native rhizospheric microbes, as currently practised. Thus, it is necessary to explore the native rhizospheric microbiome of pigeonpea plants grown in sick plots to isolate and assess candidate microbes. In the present investigation, four isolates from the 28 Pseudomonas spp. and Trichoderma spp. were selected, namely Pseudomonas spp. P‐9 and P‐28, and Trichoderma spp. K‐1 and K‐2, based on their biochemical and antagonistic characterization. All four isolates exhibited significant plant growth‐promoting abilities and showed higher antagonistic potential against the wilt phytopathogen. Phylogenetic studies revealed the selected Pseudomonas spp. isolates closer to Pseudomonas aeruginosa, Pseudomonas fluorescens , and Pseudomonas azotoformans . Similarly, the selected Trichoderma spp. isolates were identified as Trichoderma atroviride , marking the first report of its isolation from the pigeonpea rhizosphere. The selected isolates also enhanced plant defence responses to the phytopathogen by upregulating PAL, PO, CAT, and lignification, indicating multifaceted traits. Thus, the isolates can be considered potential candidates for biological control and the development of synthetic microbial communities.