Tobacco Plant Growth-Promoting and Antifungal Activities of Three Endophytic Yeast Strains

Abstract

In this research, the biosynthetic and biocontrol potential of endophytic yeast to improve the growth and development of tobacco has been elucidated. Three yeast strains were enriched and isolated from different plant tissues. Partial sequence analysis of ITS5-5.8-ITS4 region of the nuclear ribosomal DNA with universal primers identified YD5, YE1, and YSW1 as Saccharomyces cerevisiae (S. cerevisiae), Zygosaccharomyces bailii (Z. bailii), and Saccharomyces kudriavzevii (S. kudriavzevii), respectively. When cultivated in a medium supplemented with 0.1% L-tryptophan, isolated yeast strains produced indole-3-acetic acid (IAA). The capacities of those strains to improve the mobility of phosphorus and synthesize siderophores has been proven. Their antimicrobial activities against several Solanaceae plant pathogenic fungi (Alternaria solani pathovar. tobacco, Rhizoctonia solani, and Fusarium solani pathovar. phaseoli) were determined. S. cerevisiae YD5, Z. bailii YE1, and S. kudriavzevii YSW1 inhibited the growth of all tested pathogens. Yeast strains were tested for endophytic colonization of tobacco by two different inoculation methods: soil drench (SD) and leaf spraying (LS). To establish colonization in the various tissues of tested tobacco (Nicotiana tabaccum L.) plants, samples were taken on the seventh, fourteenth, and twenty-first days after treatment (DAT), and explants were inoculated on yeast malt agar (YMA). Both techniques of inoculation showed a high frequency of colonization from 83.33% to 100%. To determine the effectiveness of the microbial endophytes, their effect on some physiological processes in the plant were analyzed, such as photosynthesis, stomatal conductivity, and transpiration intensity. The effect of single and double treatment with yeast inoculum on the development and biochemical parameters of tobacco was reported. Plants have the ability of structural and functional adaptation to stress effects of different natures. All treated plants had a higher content of photosynthetic pigments compared to the control. Photosynthesis is probably more intense, and growth stimulation has been observed. The chlorophyll a/b ratio remained similar, and the total chlorophyll/carotenoid ratio slightly increased as a result of elevated chlorophyll levels. The most significant stimulating effect was recorded in tobacco plants treated by foliar spraying with Z. bailii YE1 and S. cerevisiae YD5. In contrast, S. kudriavzevii YSW1 had a better effect when applied as a soil drench. Thus, S. cerevisiae YD5, Z. bailii YE1, and S. kudriavzevii YSW1 have a high potential to be used as a biocontrol agents in organic agriculture.

Changes and Correlation Between Physiological Characteristics of Rhododendron simsii and Soil Microbial Communities Under Heat Stress

“…Hu et al (2022) concluded that Mortierella could significantly increase soil soluble organic carbon, available nitrogen and related enzyme activities, and interoperate with microorganisms. It has been shown that Candida has the ability to dissolve inorganic phosphorus and produce IAA, and has biological control and soil remediation functions, which can promote plant germination and R. simsii growth as well as increase resistance to adversity stresses (Petkova et al, 2022). This is generally consistent with the results of the present study.…”

Effects of temporal and spatial scales on soil yeast communities in the peach orchard

“…In addition, the abundance of the shared dominant genera Zygosaccharomyces and Aureobasidium increased significantly in 8- and 15-year-old peach soils, respectively. Zygosaccharomyces has been reported to be involved in the solubilization of soil insoluble phosphate, which may be related to the high phosphorus demand of 8-year-old peach trees ( Gizaw et al, 2017 ; Petkova et al, 2022 ). Moreover, 8-year-old peach trees may accumulate pathogenic fungi with increasing age, and Zygosaccharomyces also has the ability to produce siderophore compounds (iron (III) ion compounds) that inhibit the growth of fungal phytopathogens ( Hider and Kong, 2010 ; Petkova et al, 2022 ).…”

“…Zygosaccharomyces has been reported to be involved in the solubilization of soil insoluble phosphate, which may be related to the high phosphorus demand of 8-year-old peach trees ( Gizaw et al, 2017 ; Petkova et al, 2022 ). Moreover, 8-year-old peach trees may accumulate pathogenic fungi with increasing age, and Zygosaccharomyces also has the ability to produce siderophore compounds (iron (III) ion compounds) that inhibit the growth of fungal phytopathogens ( Hider and Kong, 2010 ; Petkova et al, 2022 ). Aureobasidium has been shown to be effective against postharvest fruit pathogens ( Di Francesco et al, 2020 ; Podgórska-Kryszczuk, 2023 ).…”

Diversity of duckweed (<i>Lemnaceae</i>) associated yeasts and their plant growth promoting characteristics

“…Furthermore, many plants associated with yeasts were reported to possess plant growth promoting capabilities. For example, endophytic yeasts from agriculturally grown fruits produced IAA [100] , while endophytic yeasts from strawberry ( Fragaria × ananassa ) leaves and wheat ( Triticum aestivum ) seeds were positively identified for phosphate solubilization, siderophore production, proteolytic activity, and ammonia production [111] . The diversity of ascomycetous and basidiomycetous yeast species from duckweed may lead to potential and valuable applications.…”