Li Shengnan, Lu Ke, Zhang La, Fan Lianxue, Lv Wei, Liu Da Jun, Feng Guojun
Key Laboratory of Sugar Beet Genetic Breeding, College of Heilongjiang Province, College of Advanced Agriculture and Ecological Environment, Heilongjiang University, Harbin, 150080, China.
Sugar Beet Engineering Research Center of Heilongjiang Province, Harbin, 150080, China.
Plant Mol Biol. 2024 Sep 27;114(5):107. doi: 10.1007/s11103-024-01504-2.
Cucumber (Cucumis sativus L.) is a major vegetable crop grown globally, with a cultivation history of more than 3000 years. The limited genetic diversity, low rate of intraspecific variation, and extended periods of traditional breeding have resulted in slow progress in their genetic research and the development of new varieties. Gamma (γ)-ray irradiation potentially accelerates the breeding progress; however, the biological and molecular effects of γ-ray irradiation on cucumbers are unknown. Exposing cucumber seeds to 0, 50, 100, 150, 200, and 250 Gy doses of Co-γ-ray irradiation, this study aimed to investigate the resulting phenotype and physiological characteristics of seedling treatment to determine the optimal irradiation dose. The results showed that low irradiation doses (50-100 Gy) enhanced root growth, hypocotyl elongation, and lateral root numbers, promoting seedling growth. However, high irradiation doses (150-250 Gy) significantly inhibited seed germination and growth, decreasing the survival rate of seedlings. More than 100 Gy irradiation significantly decreased the total chlorophyll content while increasing the malondialdehyde (MDA) and HO content in cucumber. Transcriptome sequencing analysis at 0, 50, 100, 150, 200, and 250 Gy doses showed that gene expression significantly differed between low and high irradiation doses. Gene Ontology enrichment and functional pathway enrichment analyses revealed that the auxin response pathway played a crucial role in seedling growth under low irradiation doses. Further, gene function analysis revealed that small auxin up-regulated gene CsSAUR37 was a key gene that was overexpressed in response to low irradiation doses, promoting primary root elongation and enhancing lateral root numbers by regulating the expression of protein phosphatase 2Cs (PP2Cs) and auxin synthesis genes.
黄瓜（Cucumis sativus L.）是全球种植的主要蔬菜作物，种植历史超过3000年。遗传多样性有限、种内变异率低以及传统育种周期长，导致其遗传研究和新品种开发进展缓慢。γ射线辐照有可能加快育种进程；然而，γ射线辐照对黄瓜的生物学和分子效应尚不清楚。本研究将黄瓜种子分别用0、50、100、150、200和250 Gy剂量的Co-γ射线辐照，旨在研究辐照处理后幼苗的表型和生理特性，以确定最佳辐照剂量。结果表明，低辐照剂量（50-100 Gy）可促进根系生长、下胚轴伸长和侧根数量增加，从而促进幼苗生长。然而，高辐照剂量（150-250 Gy）显著抑制种子萌发和生长，降低幼苗成活率。超过100 Gy的辐照显著降低黄瓜总叶绿素含量，同时增加丙二醛（MDA）和过氧化氢（H₂O₂）含量。对0、50、100、150、200和250 Gy剂量进行转录组测序分析表明，低辐照剂量和高辐照剂量之间基因表达存在显著差异。基因本体富集分析和功能途径富集分析表明，生长素响应途径在低辐照剂量下对幼苗生长起关键作用。此外，基因功能分析表明，小生长素上调基因CsSAUR37是一个关键基因，在低辐照剂量下过表达，通过调节蛋白磷酸酶2C（PP2Cs）和生长素合成基因的表达促进主根伸长并增加侧根数量。
