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Adverse environmental stresses affect plant growth and crop yields. Sheepgrass (Leymus chinensis (Trin.) Tzvel), an important forage grass that is widely distributed in the east of Eurasia steppe, has high tolerance to extreme low temperature. Many genes that respond to cold stress were identified in sheepgrass by RNA‐sequencing, but more detailed studies are needed to dissect the function of those genes. Here, we found that LcFIN2, a sheepgrass freezing‐induced protein 2, encoded a chloroplast‐targeted protein. Expression of LcFIN2 was upregulated by freezing, chilling, NaCl and abscisic acid (ABA) treatments. Overexpression of LcFIN2 enhanced the survival rate of transgenic Arabidopsis after freezing stress. Importantly, heterologous expression of LcFIN2 in rice exhibited not only higher survival rate but also accumulated various soluble substances and reduced membrane damage in rice under chilling stress. Furthermore, the chlorophyll content, the quantum photochemistry efficiency of photosystem II (ΦPSII), the non‐photochemical quenching (NPQ), the net photosynthesis rate (Pn) and the expression of some chloroplast ribosomal‐related and photosynthesis‐related genes were higher in the transgenic rice under chilling stress. These findings suggested that the LcFIN2 gene could potentially be used to improve low‐temperature tolerance in crops. [ABSTRACT FROM AUTHOR]

LcbHLH92, a pleiotropic gene from sheepgrass, negatively regulates anthocyanins/proanthocyandins and reduces seed dormancy in transgenic Arabidopsis. Sheepgrass (Leymus chinensis) is an important native forage grass, and it is widely grown in north China. Differential dormancy exists in sheepgrass germplasms with different seed colors. To decipher and find potential genes underlying this phenomenon, we compared the transcript profiles of yellow seeds with weak dormancy and brown seeds with strong dormancy. We identified a transcription factor gene LcbHLH92 which is negatively correlated with those of anthocyanin/proanthocyanidin-specific pathway genes, anthocyanidin synthase (ANS) and anthocyanidin reductase (ANR). LcbHLH92 had two transcripts, LcbHLH92a and LcbHLH92b, and their expression could be induced by abscisic acid, cold, and NaCl. Overexpression of LcbHLH92a or LcbHLH92b in Arabidopsis significantly inhibited the transcript levels of dihydroflavonol reductase (DFR) and ANS genes in leaves and seeds, which resulted in a decrease in anthocyanins and proanthocyanidins, respectively. Importantly, transgenic Arabidopsis seeds with a yellow color showed a higher germination rate than did the wild-type with a brown seed color. Moreover, LcbHLH92a and LcbHLH92b repressed the transcription of Transparent Testa8, ANS, DFR, and ANR, possibly by elevating the transcript levels of jasmonate-ZIM domain proteins through binding to their promoters. Together, our results demonstrate that LcbHLH92a and LcbHLH92b are negative regulators of the anthocyanin/proanthocyanidin pathway and influence seed dormancy. [ABSTRACT FROM AUTHOR]

As a perennial forage crop broadly distributed in eastern Eurasia, sheepgrass ( Leymus chinensis ( Trin.) Tzvel) is highly tolerant to low-temperature stress. Previous report indicates that sheepgrass is able to endure as low as −47.5 °C,allowing it to survive through the cold winter season. However, due to the lack of sufficient studies, the underlying mechanism towards the extraordinary low-temperature tolerance is unclear. Although the transcription profiling has provided insight into the transcriptome response to cold stress, more detailed studies are required to dissect the molecular mechanism regarding the excellent abiotic stress tolerance. In this work, we report a novel transcript factor Lc FIN1 ( L. chinensis freezing-induced 1) from sheepgrass. Lc FIN1 showed no homology with other known genes and was rapidly and highly induced by cold stress, suggesting that Lc FIN1 participates in the early response to cold stress. Consistently, ectopic expression of Lc FIN1 significantly increased cold stress tolerance in the transgenic plants, as indicated by the higher survival rate, fresh weight and other stress-related indexes after a freezing treatment. Transcriptome analysis showed that numerous stress-related genes were differentially expressed in Lc FIN1-overexpressing plants, suggesting that Lc FIN1 may enhance plant abiotic stress tolerance by transcriptional regulation. Electrophoretic mobility shift assays and CHIP- qPCR showed that Lc CBF1 can bind to the CRT/ DRE cis-element located in the promoter region of Lc FIN1, suggesting that Lc FIN1 is directly regulated by Lc CBF1. Taken together, our results suggest that Lc FIN1 positively regulates plant adaptation response to cold stress and is a promising candidate gene to improve crop cold tolerance. [ABSTRACT FROM AUTHOR]

As a perennial forage crop broadly distributed in eastern Eurasia, sheepgrass (Leymus chinensis (Trin.) Tzvel) is highly tolerant to low-temperature stress. Previous report indicates that sheepgrass is able to endure as low as -47.5 °C,allowing it to survive through the cold winter season. However, due to the lack of sufficient studies, the underlying mechanism towards the extraordinary low-temperature tolerance is unclear. Although the transcription profiling has provided insight into the transcriptome response to cold stress, more detailed studies are required to dissect the molecular mechanism regarding the excellent abiotic stress tolerance. In this work, we report a novel transcript factor LcFIN1 (L. chinensis freezing-induced 1) from sheepgrass. LcFIN1 showed no homology with other known genes and was rapidly and highly induced by cold stress, suggesting that LcFIN1 participates in the early response to cold stress. Consistently, ectopic expression of LcFIN1 significantly increased cold stress tolerance in the transgenic plants, as indicated by the higher survival rate, fresh weight and other stress-related indexes after a freezing treatment. Transcriptome analysis showed that numerous stress-related genes were differentially expressed in LcFIN1-overexpressing plants, suggesting that LcFIN1 may enhance plant abiotic stress tolerance by transcriptional regulation. Electrophoretic mobility shift assays and CHIP-qPCR showed that LcCBF1 can bind to the CRT/DRE cis-element located in the promoter region of LcFIN1, suggesting that LcFIN1 is directly regulated by LcCBF1. Taken together, our results suggest that LcFIN1 positively regulates plant adaptation response to cold stress and is a promising candidate gene to improve crop cold tolerance., (© 2015 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.)