Department of Biological Sciences and Temasek Life Sciences Laboratory, National University of Singapore, Singapore, Republic of Singapore.
PLoS One. 2011 Apr 20;6(4):e19033. doi: 10.1371/journal.pone.0019033.
The conserved SNF1/AMPK/SnRK1 complexes are global regulators of metabolic responses in eukaryotes and play a key role in the control of energy balance. Although α-type subunits of the SnRK1 complex have been characterized in several plant species, the biological function of β-type and γ-type subunits remains largely unknown. Here, we characterized AtPV42a and AtPV42b, the two homologous genes in Arabidopsis, which encode cystathionine-β-synthase (CBS) domain-containing proteins that belong to the PV42 class of γ-type subunits of the plant SnRK1 complexes.
METHODOLOGY/PRINCIPAL FINDINGS: Real-time polymerase chain reaction was performed to examine the expression of AtPV42a and AtPV42b in various tissues. Transgenic plants that expressed artificial microRNAs targeting these two genes were created. Reproductive organ development and fertilization in these plants were examined by various approaches, including histological analysis, scanning electron microscopy, transmission electron microscopy, and phenotypic analyses of reciprocal crosses between wild-type and transgenic plants. We found that AtPV42a and AtPV42b were expressed in various tissues during different developmental stages. Transgenic plants where AtPV42a and AtPV42b were simultaneously silenced developed shorter siliques and reduced seed sets. Such low fertility phenotype resulted from deregulation of late stamen development and impairment of pollen tube attraction conferred by the female gametophyte.
Our results demonstrate that AtPV42a and AtPV42b play redundant roles in regulating male gametogenesis and pollen tube guidance, indicating that the Arabidopsis SnRK1 complexes might be involved in the control of reproductive development.
保守的 SNF1/AMPK/SnRK1 复合物是真核生物代谢反应的全局调节剂，在能量平衡的控制中起着关键作用。尽管已经在几种植物物种中鉴定出了 SnRK1 复合物的α型亚基，但β型和γ型亚基的生物学功能在很大程度上仍然未知。在这里，我们鉴定了拟南芥中的两个同源基因 AtPV42a 和 AtPV42b，它们编码半胱氨酸-β-合酶 (CBS) 结构域包含蛋白，属于植物 SnRK1 复合物的 PV42 类 γ 型亚基。
方法/主要发现：通过实时聚合酶链反应检测 AtPV42a 和 AtPV42b 在各种组织中的表达。创建了表达针对这两个基因的人工 microRNA 的转基因植物。通过各种方法检查这些植物的生殖器官发育和受精，包括组织学分析、扫描电子显微镜、透射电子显微镜以及野生型和转基因植物之间正反交的表型分析。我们发现 AtPV42a 和 AtPV42b 在不同发育阶段的各种组织中表达。同时沉默 AtPV42a 和 AtPV42b 的转基因植物发育出更短的蒴果和减少的种子。这种低育性表型是由于晚期雄蕊发育的失调和雌性配子体赋予的花粉管吸引受损所致。
我们的结果表明，AtPV42a 和 AtPV42b 在调节雄性配子发生和花粉管导向中起冗余作用，表明拟南芥 SnRK1 复合物可能参与生殖发育的控制。
