PJB-2017-659
CHANGE IN BIOMASS, IAA LEVELS AND AUXIN SIGNALING- RELATED GENE EXPRESSION IN SHGANXIN POPLAR SEEDLINGS (POPULUS DAVIDIANA× P. ALBA VAR. PYRAMIDALIS) INDUCED BY TRICHODERMA ASPERELLUM
RONGSHU ZHANG
Abstract
Trichoderma spp. in the rhizosphere has been proposed to significantly increase the growth and yield of some plant species. These fungi are potentially involved in changes in IAA production via interactions between the host plant and rhizosphere microflora. The aim of this study was to elucidate the direct plant growth-promoting activity of live T. asperellum ACCC30536 (Ta30536) conidia. The roots and shoots of tissue-cultured poplar (Populus davidiana P. alba var. pyramidalis) seedlings were significantly affected by 60 days of treatment with Ta30536 under field conditions, with increases of 30.1% and 20.9% in total fresh and dry weight, respectively, and increases of moisture content, compared to the control group (Con). Moreover, endogenous IAA in the leaves of poplar seedlings was consistently maintained at higher levels in treated plants than in Con, reaching their highest level (1.461 μg/mL FW) at 11:00 am on the first day of continuous 15-day Ta30536 treatment. Simultaneously, RT-qPCR analysis showed that the auxin signaling-related genes PodaARF, PodaAUX/IAA, PodaGH3 and PodaSAUR were differentially expressed in treated seedlings compared to Con within 48 h of Ta30536 treatment. In addition, Pearson correlation analysis revealed that the correlation among the expression of these four genes was greatly altered in the treated plants versus Con. All differences between treated and Con plants likely resulted from exposure to T. asperellum conidia. The results of this study provide valuable insights into the effects of growth stimulation by T. asperellum ACCC30536, which likely involve an auxin-related molecular mechanism.
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