Auxin-producing fungal endophytes promote growth of sunchoke

Abstract

Endophytic fungi were able to protect their host plants against pathogens and promote plant growth. No previous studies have been conducted on the growth promotion of sunchoke by endophytic fungi. This research was the first to characterize plant growth promoting properties of endophytic fungi including, Macrophomina phaseolina BUP2/3 and Diaporthe phaseolorum BUP3/1 isolated from sunchoke and Daldinia eschscholtzii 2NTYL11, Trichoderma koningii ST-KKU1, Trichoderma erinaceum ST-KKU2, Macrophomina phaseolina SS1L10 and Macrophomina phaseolina SS1R10 from medicinal plants. Also, their plant growth promoting efficiency in artichoke plants under greenhouse condition was evaluated. The highest phosphate solubility and production of extracellular enzymes including amylase, protease, cellulase and xylanase were found after 5 and 21 days of incubation, respectively. Moreover, Indole-3-Acetic Acid (IAA) in the crude extracts of fungi isolated from Jerusalem artichoke was higher than that from medicinal plants (p ≤ 0.05). HPLC analysis suggested the putative IAA biosynthesis pathways in our fungi were via Indole-3-lactic acid (ILA) and Indole-3-acetamide (IAM). In the pot experiment, the values of height, diameter, chlorophyll content and leaf dry weight in sunchoke plants inoculated with fungal endophytes were significantly higher than those of un-inoculated plants. Therefore, this study suggested that fungal endophytes could be used as a biofertilizer for promoting growth of sunchoke.