Zhang Zhaoning, Zhao Qiang, Wang Weiyu, Feng Ruiqi, Cao Yu, Wang Guangda, Du Jidao, Du Yanli
College of Agriculture, Heilongjiang Bayi Agricultural University, Daqing, 163319, China; Crop Germplasm Resource Innovation Laboratory, National Coarse Cereals Engineering Research Center, Daqing, 163319, China.
College of Agriculture, Heilongjiang Bayi Agricultural University, Daqing, 163319, China; Crop Germplasm Resource Innovation Laboratory, National Coarse Cereals Engineering Research Center, Daqing, 163319, China.
Plant Physiol Biochem. 2025 Aug;225:110050. doi: 10.1016/j.plaphy.2025.110050. Epub 2025 May 19.
Salt stress is one of the abiotic factors limiting crop growth. However, the mechanisms regulating starch-sucrose metabolism in the mobilization of soybean (Glycine max L.) reserves at different levels of salt stress during germination remain unknown. This study evaluated the effects of different levels of salt stress [0 mmol L NaCl (CK), 75 mmol L NaCl (S), and 150 mmol L NaCl (SS)] on germinating seeds of three soybean varieties. Salt stress, especially the SS treatment, significantly reduced the radicle length, radicle fresh weight, and total fresh weight. Salt stress had different effects on the starch accumulation of cotyledons and radicles, while significantly increased the sucrose accumulation through several mechanisms. The regulatory mechanisms governing starch-sucrose metabolism in cotyledon and radicle during the germination stage exhibit distinct differences. In cotyledons, the decrease of starch content under S and SS treatment was due to the decrease of sucrose decomposition, which inhibited the metabolic cycle of starch. The up-regulated expression of GmSWEET6/15 under different levels of salt stress can promote the accumulation of sucrose in radicles. However, different salt stress levels have different response mechanisms to sucrose and starch metabolism in radicles. The activities of sucrose-metabolizing enzymes sucrose synthase (cleavage) and invertase in the radicle of S treatment were significantly reduced, while SS treatment could activate the sucrose metabolic cycle and increase the efficiency of starch-sucrose conversion. Compared with S treatment, the accumulation of starch content in SS treatment was due to the increase of SSS, α-amylase and β-amylase activities and the up-regulation of GmAMY3 and GmBAM1 expression levels. Based on the results of this study, in order to promote soybean germination in saline soils, rationalized soybean seed compositions can be designed according to the degree of salinity in each region, which can provide a reference to the future breeding of salt-tolerant soybeans.
盐胁迫是限制作物生长的非生物因素之一。然而，在发芽过程中不同盐胁迫水平下大豆（Glycine max L.）储备动员过程中调节淀粉 - 蔗糖代谢的机制仍不清楚。本研究评估了不同水平盐胁迫[0 mmol L NaCl（对照）、75 mmol L NaCl（S）和150 mmol L NaCl（SS）]对三个大豆品种发芽种子的影响。盐胁迫，尤其是SS处理，显著降低了胚根长度、胚根鲜重和总鲜重。盐胁迫对子叶和胚根的淀粉积累有不同影响，同时通过多种机制显著增加了蔗糖积累。发芽阶段子叶和胚根中淀粉 - 蔗糖代谢的调控机制表现出明显差异。在子叶中，S和SS处理下淀粉含量的降低是由于蔗糖分解减少，从而抑制了淀粉的代谢循环。不同盐胁迫水平下GmSWEET6/15的上调表达可促进胚根中蔗糖的积累。然而，不同盐胁迫水平对胚根中蔗糖和淀粉代谢有不同的响应机制。S处理的胚根中蔗糖代谢酶蔗糖合酶（裂解）和转化酶的活性显著降低，而SS处理可激活蔗糖代谢循环并提高淀粉 - 蔗糖转化效率。与S处理相比，SS处理中淀粉含量的积累是由于SSS、α - 淀粉酶和β - 淀粉酶活性的增加以及GmAMY3和GmBAM1表达水平的上调。基于本研究结果，为促进盐碱地大豆发芽，可根据各地区盐度程度设计合理的大豆种子组成，这可为未来耐盐大豆育种提供参考。
