Liu Youjie, Zhang Hanyao, Zhao Ke, Wei Xiuqing, Li Liang, Tang Yajun, Xiong Yueming, Xu Jiahui
Fruit Science Institute, Fujian Academy of Agricultural Sciences, Fuzhou 350013, China.
Key Laboratory of Biodiversity Conservation in Southwest China, National Forest and Grassland Administration, Southwest Forestry University, Kunming 650224, China.
Plants (Basel). 2024 Nov 2;13(21):3092. doi: 10.3390/plants13213092.
Pitaya () fruit is an attractive, nutrient-rich tropical fruit with commercial value. However, low-temperature stress severely affects the yield and quality of pitaya. The relevant mechanisms involved in the response of pitaya to low-temperature stress remain unclear. To study whether the SWEET gene family mediates the response of to low-temperature stress and the related mechanisms, we performed genome-wide identification of the SWEET gene family in pitaya, and we used 'Baiyulong' tissue-cultured plantlets as material in the present study. We identified 28 members of the SWEET gene family from the genome and divided these family members into four groups. Members of this gene family presented some differences in the sequences of introns and exons, but the gene structure, especially the motifs, presented relatively conserved characteristics. The promoter regions of most have multiple stress- or hormone-related cis-elements. Three duplicated gene pairs were identified, including one tandem duplication gene and two fragment duplication gene pairs. The results revealed that the genes may regulate the transport and distribution of soluble sugars in plants; indirectly regulate the enzyme activities of CAT, POD, and T-SOD through its expression products; and are involved in the response of pitaya to low-temperature stress and play vital roles in this process. After ABA and MeJA treatment, the expression of changed significantly, and the cold stress was also alleviated. This study elucidated the molecular mechanism and physiological changes in the gene in sugar metabolism and distribution of pitaya when it experiences low-temperature stress and provided a theoretical basis for cold-resistant pitaya variety breeding.
火龙果是一种具有吸引力、营养丰富且具有商业价值的热带水果。然而，低温胁迫严重影响火龙果的产量和品质。火龙果对低温胁迫响应的相关机制尚不清楚。为了研究SWEET基因家族是否介导火龙果对低温胁迫的响应及其相关机制，我们对火龙果中的SWEET基因家族进行了全基因组鉴定，并在本研究中以‘白玉龙’组培苗为材料。我们从基因组中鉴定出28个SWEET基因家族成员，并将这些家族成员分为四组。该基因家族成员的内含子和外显子序列存在一些差异，但基因结构，尤其是基序，呈现出相对保守的特征。大多数基因的启动子区域有多个与胁迫或激素相关的顺式元件。鉴定出三对重复基因对，包括一对串联重复基因和两对片段重复基因对。结果表明，该基因可能调控植物中可溶性糖的运输和分配；通过其表达产物间接调控CAT、POD和T-SOD的酶活性；并参与火龙果对低温胁迫的响应，在此过程中发挥重要作用。经ABA和MeJA处理后，该基因的表达发生显著变化，冷胁迫也得到缓解。本研究阐明了火龙果在低温胁迫时该基因在糖代谢和分配中的分子机制及生理变化，为火龙果抗寒品种选育提供了理论依据。
