AsHSP17, a creeping bentgrass small heat shock protein modulates plant photosynthesis and ABA‐dependent and independent signalling to attenuate plant response to abiotic stress

Abstract

Heat shock proteins (HSPs) are molecular chaperones that accumulate in response to heat and other abiotic stressors. Small HSPs (sHSPs) belong to the most ubiquitous HSP subgroup with molecular weights ranging from 12 to 42 kDa. We have cloned a new sHSP gene, AsHSP17 from creeping bentgrass (Agrostis stolonifera) and studied its role in plant response to environmental stress. AsHSP17 encodes a protein of 17 kDa. Its expression was strongly induced by heat in both leaf and root tissues, and by salt and abscisic acid (ABA) in roots. Transgenic Arabidopsis plants constitutively expressing AsHSP17 exhibited enhanced sensitivity to heat and salt stress accompanied by reduced leaf chlorophyll content and decreased photosynthesis under both normal and stressed conditions compared to wild type. Overexpression of AsHSP17 also led to hypersensitivity to exogenous ABA and salinity during germination and post-germinative growth. Gene expression analysis indicated that AsHSP17 modulates expression of photosynthesis-related genes and regulates ABA biosynthesis, metabolism and ABA signalling as well as ABA-independent stress signalling. Our results suggest that AsHSP17 may function as a protein chaperone to negatively regulate plant responses to adverse environmental stresses through modulating photosynthesis and ABA-dependent and independent signalling pathways.

Transgenic creeping bentgrass overexpressing Osa‐miR393a exhibits altered plant development and improved multiple stress tolerance

“…For example, the accumulation of a small HSP, HSP25, was positively correlated with the thermotolerance in creeping bentgrass (Park et al ., ). To investigate the mechanism of miR393‐mediated plant response to heat stress at molecular level, we analysed expression of AsHSP17.0 and AsHSP26.7a , the two small HSP genes responding to high temperature in wild‐type and transgenic plants (Li et al ., , ; Sun et al ., ). Quantitative RT–PCR shows that AsHSP17.0 and AsHSP26.7a are induced during heat stress in both transgenic plants and controls, but the expression levels are higher in transgenics than in wild‐type controls (Figure f,g).…”

The CsHSP17.2 molecular chaperone is essential for thermotolerance in Camellia sinensis

“…Interestingly, CsHSP17.2 transcription was down-regulated by ABA treatment, which was consistent with the results of Sun et al . 31 , suggesting that CsHSP17.2 may function in an ABA-dependent manner.…”

Ectopic expression of a cyanobacterial flavodoxin in creeping bentgrass impacts plant development and confers broad abiotic stress tolerance

“…They bind and stabilize their client proteins that have become denatured under stress conditions. Most of them are highly up‐regulated in response to heat and have a clear role in thermotolerance (Atkinson and Urwin, ; Merino et al ., ; Sun et al ., ; Waters, ). Three AsHSP genes examined in this study, AsHSP17 (Sun et al ., ), AsHSP26.7 and AsHSP26.8 (Wang and Luthe, ), were all significantly induced, but differentially regulated in WT and the TG plants (Figure ), suggesting Fld implication in triggering one of the important stress response mechanisms, contributing to an enhanced plant tolerance to heat.…”