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Leymus chinensis (Trin.) Tzvel. is a perennial rhizome grass of the Poaceae (also called Gramineae) family, which adapts well to drought, saline and alkaline conditions. However, little is known about the stress tolerance of L. chinensis at the molecular level. microRNAs (miRNAs) are known to play critical roles in nutrient homeostasis, developmental processes, pathogen responses, and abiotic stress in plants. In this study, we used Solexa sequencing technology to generate high-quality small RNA data from three L. chinensis groups: a control group, a saline-alkaline stress group (100 mM NaCl and 200 mM NaHCO3), and a drought stress group (20% polyethylene glycol 2000). From these data we identified 132 known miRNAs and 16 novel miRNAs candidates. For these miRNAs we also identified target genes that encode a broad range of proteins that may be correlated with abiotic stress regulation. This is the first study to demonstrate differentially expressed miRNAs in L. chinensis under saline-alkali and drought stress. These findings may help explain the saline-alkaline and drought stress responses in L. chinensis. [ABSTRACT FROM AUTHOR]

Soybean (Glycine max) is one of the important oil crops worldwide. In recent years, environmental stresses such as drought and soil salinization have severely deteriorated soybean yield and quality. We investigated the overexpression of the transcription factor GmTGA15 in response to drought stress in transgenic soybean hairy roots and Arabidopsis plants. The results of quantitative real time polymerase chain reaction (qRT-PCR) analyses showed that GmTGA15 was greatly induced by salt, PEG6000, salicylic acid (SA), gibberellic acid (GA), abscisic acid (ABA), and methyl jasmonate (MeJA) in soybean. In response to drought stress, the contents of both chlorophyll and proline were significantly increased, while the content of malondialdehyde (MDA) was significantly decreased in the soybean hairy roots with the overexpression of GmTGA15 in comparison to wild type (WT). Under the simulated drought conditions, the transgenic Arabidopsis plants showed significantly longer roots and lower mortality than that of the wild type. These results suggest that GmTGA15 promotes tolerance to drought stress in both soybean and Arabidopsis plants. This study provides the scientific evidence for further functional analysis of soybean TGA transcription factors in drought stress and the breeding of drought-resistance crops. [ABSTRACT FROM AUTHOR]