Involvement of Trichoderma asperellum strain T6 in regulating iron acquisition in plants

Abstract

Iron (Fe) deficiency is a major plant nutritional disorder in many parts of the world, particularly in areas with saline soils. Among the numerous root-associated microbes that are beneficial for plant nutrient uptake, Trichoderma spp. are the most effective rhizosphere fungi for enhancing plant growth and plant resistance to biotic and abiotic stresses. To investigate the potential mechanisms of action of Trichoderma on insoluble Fe in the soil, which is difficult for plants to absorb and utilize, a high siderophore-producing strain of Trichoderma T6, was isolated from the rhizosphere of cucumber plants. The strain was identified as T. asperellum based on the morphological features and molecular phylogenetic analyses. Applying strain T6 to sterile soil could increase soil levels of Fe(2+) and siderophores, as well as increase Fe(2+) and Fe(3+)-chelate reductase (FCR) activity in cucumber tissues. Purified siderophore eluent (PSE) increased plant growth, thus confirming its role in plant growth promotion. Moreover, extracellular Fe(3+) reducing activity and three kinds of organic acids were detected in the culture filtrate of strain T6. These results indicate that strain T6 influences plant Fe absorption in several ways. Siderophore-based Fe chelation is effective in providing Fe to plants, organic acids, and Fe(3+) reducing enzymes may participate in the solubilization and reduction of insoluble Fe(3+) to Fe(2+).

Effects of phosphate solubilization and phytohormone production of Trichoderma asperellum Q1 on promoting cucumber growth under salt stress

“…are vital to solubilization of insoluble inorganic phosphates (Rashid et al 2004). Moreover, the same three organic acids were also detected in culture broth inoculated with another T. asperellum in our laboratory and the findings have just been published recently (Zhao and Wang 2014).…”

Effect of acid phosphatase produced by Trichoderma asperellum Q1 on growth of Arabidopsis under salt stress

“…Although we have verified that the fermentation broth of T. asperellum Q1 that contains ACPase could promote plant growth by P-solubilization (Zhao and Zhang 2015), the effects of other components cannot be ruled out. T. asperellum Q1 has the ability to produce siderophore and organic acids, which have been testified in our lab (Zhao et al 2014). Some researchers have also discovered that the siderophore produced by arsenic-resistant bacteria could solubilizing P from inorganic minerals, phosphate rock and organic phytate (Ghosh et al 2015).…”

Enhancing 15N-uptake in maize (Zea mays L.) by native Trichoderma spp. strains in Central Mexico

“…The results of tomato biomass and yield implied that T. harzianum strain SQR-T037 had the capacity to recognize and adhere to the plant roots (Chen et al, 2011). The benefits of T. asperellum strain T6 on plant growth under salt stress may be related to its capacity to chelate or solubilize and reduce Fe (Zhao et al, 2014). T.…”

“…influence plant growth and development have been reported (Harman et al, 2004). Such mechanisms include the production of growth hormones (Contreras-Cornejo et al, 2009), solubilization of soil micronutrients (Ying-Tzu et al, 2018) as well as increased uptake and translocation of lessavailable nutrients (Zhao et al, 2014). Trichoderma enhanced uptake of P and N is of key importance in assessing agricultural production (Vera-Núñez et al, 2006).…”