Zhao Xinyu, Zhang Zhimeng, Ding Jiarui, Wu Chunfei, Qu Yunfeng, Song Anning, Zhao Haibin, Song Weiwei, Liu Meng, Yang Donghe, Liu Yizhuo, He Miao, Xing Qianyu, Zhang Huixin, Cui Lei, Li Xinling, Xie Jingzhong, Li Hongjie, He Fei, Zhang Yanming
Key Laboratory of Molecular Cytogenetics and Genetic Breeding of Heilongjiang Province, College of Life Science and Technology, Harbin Normal University, Harbin, 150025, China.
Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China.
Plant J. 2025 May;122(3):e70179. doi: 10.1111/tpj.70179.
Intermedium wheatgrass (Thinopyrum intermedium), a perennial species with extensive root systems and high tolerance to cold, drought, and salinity, is a valuable genetic resource for the development of perennial crops. Over a decade-long selection process, two cold-hardy perennial wheatgrass lines were developed by crossing wheat-Thinopyrum partial amphiploids with Th. intermedium. These lines inherited key traits from Th. intermedium, including plant stature, spike morphology, and postharvest regrowth. Transcriptome-based single-nucleotide polymorphism tracing and sequential multicolor genomic in situ hybridization analyses revealed variations in the chromosome compositions of the perennial wheatgrass lines. The introgression of wheat chromosomes enhanced grain weight and size, while preserving the cold-hardy, perennial characteristics of the wheatgrass lines compared to Th. intermedium. Genome-wide gene expression was generally suppressed in the wheatgrass lines relative to Th. intermedium, particularly in conserved genes. This suppression was especially pronounced in genes involved in cell division and DNA repair pathways. In contrast, genes associated with cold tolerance and the water stress response were upregulated. We identified eight cold-tolerance genes in the Th. intermedium chromosomes and validated three of them, Thint.J05G452200, Thint.J05G452300, and Thint.V05G408900, using qRT-PCR. These genes encode proteins associated with cold tolerance and are potential candidates for further functional validation. Additionally, three chromosomes from homoeologous group 6 were introgressed, carrying six genes potentially associated with superior grain traits. Among them, TraesCS6D02G287800, which encodes a specific protein, exhibited high expression levels in both wheatgrass lines, suggesting its critical role in enhancing grain traits. Our results indicate that the suppression of grass gene expression, likely due to the introgression of wheat chromosomes and the upregulation of pathways related to cold tolerance and overwintering ability, contributes to the adaptive features of the wheatgrass lines. This study provides a genomic foundation for understanding gene expression regulation in distant hybrid progeny and offers valuable insights for designing new breeding strategies for perennial wheat or wheatgrass.
中间偃麦草（Thinopyrum intermedium）是一种多年生植物，根系发达，对寒冷、干旱和盐分具有高度耐受性，是多年生作物育种的宝贵遗传资源。经过十多年的选育过程，通过将小麦-中间偃麦草部分双体与中间偃麦草杂交，培育出了两个抗寒多年生偃麦草品系。这些品系继承了中间偃麦草的关键性状，包括植株高度、穗形态和收获后的再生能力。基于转录组的单核苷酸多态性追踪和连续多色基因组原位杂交分析揭示了多年生偃麦草品系染色体组成的变异。小麦染色体的渗入增加了粒重和粒大小，同时与中间偃麦草相比，保留了偃麦草品系的抗寒多年生特性。相对于中间偃麦草，偃麦草品系全基因组基因表达普遍受到抑制，尤其是在保守基因中。这种抑制在参与细胞分裂和DNA修复途径的基因中尤为明显。相比之下，与耐寒性和水分胁迫反应相关的基因上调。我们在中间偃麦草染色体中鉴定出8个耐寒基因，并使用qRT-PCR验证了其中3个基因，即Thint.J05G452200、Thint.J05G452300和Thint.V05G408900。这些基因编码与耐寒性相关的蛋白质，是进一步功能验证的潜在候选基因。此外，同源群6的三条染色体发生了渗入，携带了六个可能与优良粒性状相关的基因。其中，编码特定蛋白质的TraesCS6D02G287800在两个偃麦草品系中均表现出高表达水平，表明其在增强粒性状方面的关键作用。我们的结果表明，偃麦草基因表达的抑制可能是由于小麦染色体的渗入以及与耐寒性和越冬能力相关途径的上调，这有助于偃麦草品系的适应性特征。本研究为理解远缘杂交后代的基因表达调控提供了基因组基础，并为设计多年生小麦或偃麦草的新育种策略提供了有价值的见解。
