茉莉酸调控马铃薯离体块茎发育的主要代谢物变化

Jasmonic Acid Regulates the Changes of Major Metabolites in Potato Tuber Development in vitro

【目的】茉莉酸(jasmonic acid,JA)是马铃薯块茎发育过程中重要调控激素之一,研究JA调控块茎发育机理将为块茎产量及品质性状形成提供重要理论基础。【方法】采用马铃薯离体匍匐茎作为供试材料,外源添加JA(0、0.5、5和50μmol·L^(-1))处理,分析JA诱导离体块茎表型形态、组织显微结构、碳水化合物积累及蛋白质组变化。【结果】随JA处理浓度升高,单个匍匐茎形成块茎数目、块茎直径及干鲜重、环髓区细胞面积、淀粉及可溶性糖含量在0.5和5μmol·L^(-1)JA处理后逐渐增加(P<0.05),而50μmol·L^(-1)JA处理后块茎直径及干鲜重、淀粉含量显著减少(P<0.05);脂氧合酶活性随JA浓度升高逐渐降低(P<0.05)。采用双向凝胶电泳(2-DE)和MALDI-TOF/TOF-MS质谱技术鉴定到JA调控块茎发育密切相关的35个差异表达蛋白质(P<0.05且差异表达倍数≥2.5倍),主要涉及生物能量与代谢(28.6%)、细胞防御(28.6%)、蛋白质生物合成与贮藏(11.4%)、信号转导(8.6%)、转录(8.6%)、未知功能(8.6%)和混杂(5.6%)。通过聚类分析将这些蛋白质差异表达模式聚为三类:第一类包括17个蛋白质,在0.5μmol·L^(-1)JA处理后下调表达,而在5μmol·L^(-1)JA处理后上调表达,主要参与生物能量与代谢、蛋白质生物合成与贮藏、信号转导、转录;第二类包括10个蛋白质,随JA浓度升高上调表达,主要参与细胞防御、生物能量与代谢、转录;第三类包括8个蛋白质,JA处理后均下调表达,主要参与生物能量与代谢、细胞防御、蛋白质生物合成与贮藏。【结论】低浓度JA(0.5和5μmol·L^(-1))主要通过诱导块茎环髓区细胞膨大、细胞内蔗糖及多糖积累、细胞防御能力来促进块茎形态建成,而高浓度JA(50μmol·L^(-1))则表现为抑制作用。

【Objective】Jasmonic acid(JA)is one of key regulatory hormones during potato tuber development.Study on JA regulating tuber development mechanism would provide an important theoretical basis for tuber yield and quality formation.【Method】In this study,potato stolons cultured in vitro were exogenously applied with JA(0,0.5,5,50μmol·L^(-1))to analyze the phenotype,tissue microstructure,carbohydrate accumulation and proteome change of tubers.【Result】With the increase of JA concentration,the tuber number formed per stolon,tuber diameter,fresh and dry weight,cell area of perimedullary zone,starch and soluble sugar content were gradually increased at 0.5 and 5μmol·L^(-1)JA(P<0.05),whereas the tuber diameter,fresh and dry weight,starch content were significantly decreased at 50μmol·L^(-1)JA(P<0.05).Lipoxygenase activity was gradually decreased with JA concentration increasing(P<0.05).Thirty-five differentially abundant proteins(P<0.05 and fold change≥2.5)closely related to tuber development regulating by JA were identified by 2-DE and MALDI-TOF/TOF-MS.They were mainly involved in bioenergy and metabolism(28.6%),cell defense and rescue(28.6%),protein biogenesis and storage(11.4%),signaling(8.6%),transcription(8.6%),unknown(8.6%)and miscellaneous(5.6%).The differential expression patterns of these proteins were clustered into three categories by hierarchical clustering analysis.Cluster 1 included 17 proteins that down-regulated at 0.5μmol·L^(-1)JA and up-regulated at 5μmol·L^(-1)JA,which mainly involved in bioenergy and metabolism,protein biogenesis and storage,signaling and transcription.Cluster 2 included 10 proteins that gradually up-regulated with JA concentration increasing,which were mainly involved in cell defense and rescue,bioenergy and metabolism,transcription.Cluster 3 included 8 proteins that down-regulated after JA treatments,which were mainly involved in bioenergy and metabolism,cell defense and rescue,protein biogenesis and storage.【Conclusion】Low JA concentration(0.5,5μmol·L^(-1))might promote tuber morphogenesis by inducing cell enlargement in tuber perimedullary zone,intracellular sucrose and polysaccharide accumulation,and cell defense ability,whereas high JA concentration(50μmol·L^(-1))showed inhibitory effects.