Data_Sheet_1_PhDHS Is Involved in Chloroplast Development in Petunia.xlsx

Deoxyhypusine synthase (DHS) is encoded by a nuclear gene and is the key enzyme involved in the post-translational activation of the eukaryotic translation initiation factor eIF5A. DHS plays important roles in plant growth and development. To gain a better understanding of DHS, the petunia (Petunia hybrida) PhDHS gene was isolated, and the role of PhDHS in plant growth was analyzed. PhDHS protein was localized to the nucleus and cytoplasm. Virus-mediated PhDHS silencing caused a sectored chlorotic leaf phenotype. Chlorophyll levels and photosystem II activity were reduced, and chloroplast development was abnormal in PhDHS-silenced leaves. In addition, PhDHS silencing resulted in extended leaf longevity and thick leaves. A proteome assay revealed that 308 proteins are upregulated and 266 proteins are downregulated in PhDHS-silenced plants compared with control, among the latter, 21 proteins of photosystem I and photosystem II and 12 thylakoid (thylakoid lumen and thylakoid membrane) proteins. In addition, the mRNA level of PheIF5A-1 significantly decreased in PhDHS-silenced plants, while that of another three PheIF5As were not significantly affected in PhDHS-silenced plants. Thus, silencing of PhDHS affects photosynthesis presumably as an indirect effect due to reduced expression of PheIF5A-1 in petunia.
Significance:PhDHS-silenced plants develop yellow leaves and exhibit a reduced level of photosynthetic pigment in mesophyll cells. In addition, arrested development of chloroplasts is observed in the yellow leaves.

脱氧羟腐胺赖氨酸合酶（Deoxyhypusine synthase, DHS）由核基因编码，是真核翻译起始因子eIF5A翻译后激活过程中的关键酶。DHS在植物生长发育过程中发挥重要调控作用。为深入解析DHS的生物学功能，本研究从矮牵牛（Petunia hybrida）中克隆得到PhDHS基因，并对其在植物生长中的功能进行了系统分析。
亚细胞定位结果显示，PhDHS蛋白定位于细胞核与细胞质中。病毒介导的PhDHS基因沉默会导致植株出现斑驳型褪绿叶片表型。与对照相比，沉默植株的叶绿素含量与光系统II活性均显著降低，且叶片叶绿体发育出现异常。此外，PhDHS沉默还可导致叶片寿命延长、叶片厚度增加。
蛋白质组学分析表明，相较于对照植株，PhDHS沉默植株中共鉴定到308个上调表达蛋白、266个下调表达蛋白；其中下调表达蛋白包含21个光系统I与光系统II相关蛋白，以及12个类囊体（类囊体腔与类囊体膜）蛋白。
转录水平检测结果显示，PhDHS沉默植株中PheIF5A-1的mRNA水平显著下调，而其余3个PheIF5A家族成员的转录水平未出现显著变化。综上，矮牵牛中PhDHS沉默可通过降低PheIF5A-1的表达量，间接影响植物的光合作用过程。
研究意义：PhDHS沉默植株会形成黄色叶片，且叶肉细胞内光合色素水平显著降低；同时，黄色叶片中可观察到叶绿体发育受阻的表型。