Yang Hongli, Wang Tianju, Yu Xinghua, Yang Yang, Wang Chunfang, Yang Qinghui, Wang Xianhong
Sugarcane Research Institute, Yunnan Agricultural University, Kunming, 650201, Yunnan Province, PR China.
Chuxiong normal university, Chuxiong, 675000, Yunnan Province, PR China.
BMC Genomics. 2020 Jul 22;21(1):507. doi: 10.1186/s12864-020-06917-z.
Wild sugarcane Saccharum spontaneum plants vary in ploidy, which complicates the utilization of its germplasm in sugarcane breeding. Investigations on cold tolerance in relation to different ploidies in S. spontaneum may promote the exploitation of its germplasm and accelerate the improvement of sugarcane varieties.
A hypoploid clone 12-23 (2n = 54) and hyperploid clone 15-28 (2n = 92) of S. spontaneum were analysed under cold stress from morphological, physiological, and transcriptomic perspectives. Compared with clone 15-28, clone 12-23 plants had lower plant height, leaf length, internode length, stem diameter, and leaf width; depressed stomata and prominent bristles and papillae; and thick leaves with higher bulliform cell groups and thicker adaxial epidermis. Compared with clone 15-28, clone 12-23 showed significantly lower electrical conductivity, significantly higher water content, soluble protein content, and superoxide dismutase activity, and significantly higher soluble sugar content and peroxidase activity. Under cold stress, the number of upregulated genes and downregulated genes of clone 12-23 was higher than clone 15-28, and many stress response genes and pathways were affected and enriched to varying degrees, particularly sugar and starch metabolic pathways and plant hormone signalling pathways. Under cold stress, the activity of 6-phosphate glucose trehalose synthase, trehalose phosphate phosphatase, and brassinosteroid-signalling kinase and the content of trehalose and brassinosteroids of clone 12-23 increased.
Compared with hyperploid clone 15-28, hypoploid clone 12-23 maintained a more robust osmotic adjustment system through sugar accumulation and hormonal regulation, which resulted in stronger cold tolerance.
野生甘蔗（Saccharum spontaneum）植株的倍性各异，这使其种质在甘蔗育种中的利用变得复杂。对野生甘蔗不同倍性的耐寒性进行研究，可能会促进其种质的开发，并加速甘蔗品种的改良。
从形态学、生理学和转录组学角度，对野生甘蔗的一个亚倍体克隆12 - 23（2n = 54）和超倍体克隆15 - 28（2n = 92）在低温胁迫下进行了分析。与克隆15 - 28相比，克隆12 - 23植株的株高、叶长、节间长度、茎直径和叶宽较低；气孔凹陷，刚毛和乳头状突起明显；叶片较厚，泡状细胞群较多，上表皮较厚。与克隆15 - 28相比，克隆12 - 23的电导率显著较低，含水量、可溶性蛋白含量和超氧化物歧化酶活性显著较高，可溶性糖含量和过氧化物酶活性显著较高。在低温胁迫下，克隆12 - 23上调基因和下调基因的数量高于克隆15 - 28，许多胁迫响应基因和途径受到不同程度的影响和富集，尤其是糖和淀粉代谢途径以及植物激素信号传导途径。在低温胁迫下，克隆12 - 23的6 - 磷酸葡萄糖海藻糖合酶、海藻糖磷酸磷酸酶和油菜素类固醇信号激酶的活性以及海藻糖和油菜素类固醇的含量增加。
与超倍体克隆15 - 28相比，亚倍体克隆12 - 23通过糖积累和激素调节维持了更强大的渗透调节系统，从而具有更强的耐寒性。
