Pugionium Cornutum (L.) Gaertn. PcHSP17.8 Gene Confers Drought Stress Tolerance To Transgenic Arabidopsis

Pugionium cornutum (L.) Gaertn. ( P. cornutum ), a member of the Brassicaceae family, is mainly distributed in desert or sandy regions in Gansu, Ningxia, and Inner Mongolia of China. Due to its strong drought tolerance, P. cornutum is an ideal material for investigating plant stress resistance mechanisms. Small heat shock proteins ( sHSPs ), with molecular weights ranging form 15 to 30 kD, are low-molecular-weight stress-responsive molecules that are induced by various environmental and developmental signals. They play a critical role in helping plants adapt to abiotic stresses, particularly drought. However, the sHSP family in P. cornutum remains poorly characterized at both the identification and functional levels. In this study, based on proteomic analysis of P. cornutum leaves under drought stress, the gene PcHSP17.8 was identified and functionally validated. The full-length open reading frame (ORF) of PcHSP17.8 is 471 bp, encoding a 156-amino acid protein that is predominantly localized in the cytoplasm. Quantitative real-time PCR (qPCR) analysis showed that PcHSP17.8 expression is tissue-specific and can be induced by drought, NaCl, low temperature (4℃), high temperature (42℃), and abscisic acid (ABA). Under drought conditions, overexpressing PcHSP17.8 exhibited enhanced germination rates and root elongation, along with reduced levels of hydrogen peroxide (H 2 O 2 ) and malondialdehyde (MDA), as well as a lower superoxide anion production rate. Furthermore, transgenic lines showed increased chlorophyll and proline content, elevated hydroxyl radical scavenging capacity, and enhanced activities of the antioxidant enzymes superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT). The transgenic lines also demonstrated a reduced water loss rate. Collectively, these findings indicated that overexpression of PcHSP17.8 enhances drought tolerance in Arabidopsis , highlighting its potential role in improving plant resistance to water deficit.