Division of Plant Biosciences, School of Applied Biosciences, College of Agriculture and Life Science, Kyungpook National University, Daegu, South Korea.
Coastal Agriculture Research Institute, Kyungpook National University, Daegu, South Korea.
Plant Biol (Stuttg). 2023 Oct;25(6):902-914. doi: 10.1111/plb.13564. Epub 2023 Aug 28.
Studies on plant responses to combined abiotic stresses are very limited, especially in major crop plants. The current study evaluated the response of chorismate mutase overexpressor (OxCM) rice line to combined UV light and drought stress. The experiments were conducted in pots in a growth chamber, and data were assessed for gene expression, antioxidant and hormone regulation, flavonoid accumulation, phenotypic variation, and amino acid accumulation. Wild-type (WT) rice had reduced the growth and vigour, while transgenic rice maintained growth and vigour under combined UV light and drought stress. ROS and lipid peroxidation analysis revealed that chorismate mutase (OsCM) reduced oxidative stress mediated by ROS scavenging and reduced lipid peroxidation. The combined stresses reduced biosynthesis of total flavonoids, kaempferol and quercetin in WT plants, but increased significantly in plants with OxCM. Phytohormone analysis showed that SA was reduced by 50% in WT and 73% in transgenic plants, while ABA was reduced by 22% in WT plants but increased to 129% in transgenic plants. Expression of chorismate mutase regulates phenylalanine biosynthesis, UV light and drought stress-responsive genes, e.g., phenylalanine ammonia lyase (OsPAL), dehydrin (OsDHN), dehydration-responsive element-binding (OsDREB), ras-related protein 7 (OsRab7), ultraviolet-B resistance 8 (OsUVR8), WRKY transcription factor 89 (OsWRKY89) and tryptophan synthase alpha chain (OsTSA). Moreover, OsCM also increases accumulation of free amino acids (aspartic acid, glutamic acid, leucine, tyrosine, phenylalanine and proline) and sodium (Na), potassium (K), and calcium (Ca) ions in response to the combined stresses. Together, these results suggest that chorismate mutase expression induces physiological, biochemical and molecular changes that enhance rice tolerance to combined UV light and drought stresses.
有关植物对非生物胁迫综合响应的研究非常有限，特别是在主要作物中。本研究评估了分支酸变位酶过表达（OxCM）水稻品系对紫外光和干旱胁迫综合作用的响应。实验在生长室中的盆中进行，并对基因表达、抗氧化和激素调节、类黄酮积累、表型变化和氨基酸积累进行了评估。野生型（WT）水稻的生长和活力降低，而转基因水稻在紫外光和干旱胁迫综合作用下保持了生长和活力。ROS 和脂质过氧化分析表明分支酸变位酶（OsCM）通过清除 ROS 减少了氧化应激并减少了脂质过氧化。综合胁迫减少了 WT 植物中总类黄酮、山柰酚和槲皮素的生物合成，但在 OxCM 植物中显著增加。植物激素分析表明，SA 在 WT 中降低了 50%，在转基因植物中降低了 73%，而 ABA 在 WT 植物中降低了 22%，但在转基因植物中增加到 129%。分支酸变位酶的表达调节苯丙氨酸生物合成、紫外光和干旱胁迫响应基因，如苯丙氨酸解氨酶（OsPAL）、脱水素（OsDHN）、脱水响应元件结合蛋白（OsDREB）、ras 相关蛋白 7（OsRab7）、紫外线-B 抗性 8（OsUVR8）、WRKY 转录因子 89（OsWRKY89）和色氨酸合酶α链（OsTSA）。此外，OsCM 还增加了游离氨基酸（天冬氨酸、谷氨酸、亮氨酸、酪氨酸、苯丙氨酸和脯氨酸）和钠（Na）、钾（K）和钙（Ca）离子的积累，以应对综合胁迫。总之，这些结果表明分支酸变位酶的表达诱导了增强水稻对紫外光和干旱胁迫综合作用耐受性的生理、生化和分子变化。
