Senescence-Inducible Expression of Isopentenyl Transferase Extends Leaf Life, Increases Drought Stress Resistance and Alters Cytokinin Metabolism in Cassava
Senescence-Inducible Expression of Isopentenyl Transferase Extends Leaf Life, Increases Drought Stress Resistance and Alters Cytokinin Metabolism in Cassava
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异戊烯基转移酶的衰老诱导表达可延长木薯的叶片寿命、增强耐旱性并改变细胞分裂素代谢
DOI：
10.1111/j.1744-7909.2010.00956.x
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发表时间：
2010-07-01
影响因子：
11.4
通讯作者：
Gruissem, Wilhelm
中科院分区：
文献类型：
--
作者：
Zhang, Peng;Wang, Wen-Quan;Gruissem, Wilhelm
木薯（Manihot esculenta Crantz）在生长过程中落叶，尤其是在热带旱季。随着 SAG12-IPT 转基因木薯的生产，我们希望通过自动调节衰老抑制系统来测试转基因植物的叶片保留水平和细胞分裂素代谢的改变。通过温室植物中的分子分析和表型检查确认转基因表达后，选择两个转基因植物系529-28和529-48进行进一步研究。经过暗诱导衰老处理后，与野生型叶子相比，529-28 植物的分离成熟叶子保留了高水平的叶绿素。品系529-28显示出显着的耐旱性，如干旱胁迫处理后的保持绿色能力所表明的。田间实验证明，与野生型和529-48植物相比，529-28植物的叶片衰老综合症显着延迟。这些植物的生理和农艺特征还表明，IPT 的诱导表达对光合作用、糖分配和氮分配有影响。重要的是，529-28植物积累了高水平的反式玉米素型细胞分裂素，特别是相应的储存O-葡萄糖苷，以维持细胞分裂素稳态。我们的研究证明了延长木本木薯叶子寿命的可行性，也为木薯叶子中细胞分裂素稳态的控制提供了线索。
Cassava (Manihot esculenta Crantz) sheds its leaves during growth, especially within the tropical dry season. With the production of SAG12-IPT transgenic cassava we want to test the level of leaf retention and altered cytokinin metabolism of transgenic plants via the autoregulatory senescence inhibition system. After confirmation of transgene expression by molecular analysis and phenotype examination in greenhouse plants, two transgenic plant lines, 529-28 and 529-48, were chosen for further investigation. Detached mature leaves of 529-28 plants retained high levels of chlorophyll compared with wild-type leaves after dark-induced senescence treatment. Line 529-28 showed significant drought tolerance as indicated by stay-green capacity after drought stress treatment. Field experiments proved that leaf senescence syndrome was significantly delayed in 529-28 plants in comparison with wild-type and 529-48 plants. Physiological and agronomical characterizations of these plants also revealed that the induced expression of IPT had effects on photosynthesis, sugar allocation and nitrogen partitioning. Importantly, the 529-28 plants accumulated a high level of trans-zeatin-type cytokinins particularly of corresponding storage O-glucosides to maintain cytokinin homeostasis. Our study proves the feasibility of prolonging the leaf life of woody cassava and also sheds light on the control of cytokinin homeostasis in cassava leaves.