Section of Molecular Cell and Developmental Biology, University of Texas at Austin, 1 University Station A6700, Austin TX 78712, USA.
Plant Physiol Biochem. 2013 Aug;69:62-73. doi: 10.1016/j.plaphy.2013.04.022. Epub 2013 May 17.
An NCBI nucleotide blast keyed to apyrase (ATP-diphosphohydrolases, EC 3.6.1.5) conserved regions revealed five apyrases, AtAPYs (3-7), in addition to the previously identified AtAPY1 and 2. Here we report the functional analyses of two of the newly defined apyrases, AtAPY6 and AtAPY7. We analyzed tissue specificity of AtAPY6 and 7 expression by qRT-PCR and promoter:GUS fusion assays. We characterized the phenotypes of single and double knockout mutants for AtAPY6 and 7 in anther and pollen by light microscopy and electron microscopy. The transcripts of both AtAPY6 and 7 are expressed in mature pollen grains. Single knockout mutants of AtAPY6 and 7 displayed a minor change in pollen exine pattern under scanning electron microscopy without obvious change in fertility. Double knockout mutants of AtAPY6 and 7 (apy6apy7) displayed severe defects in pollen exine pattern, deformed pollen shape and reduced male fertility. An analysis of pollen from heterozygous apy6apy7 plants suggests that the defects in pollen exine wall are determined by the diploid genome. Our findings demonstrate that AtAPY6 and AtAPY7 are enzymes that play an important role in exine development of pollen grains, possibly through regulating the production of key polysaccharides needed for proper assembly of the exine layer.
通过对 Apyrase（ATP-二磷酸水解酶，EC 3.6.1.5）保守区域的 NCBI 核苷酸比对，发现了 5 种 Apyrase，AtAPYs（3-7），除了之前鉴定的 AtAPY1 和 2 之外。在这里，我们报告了两种新定义的 Apyrase，AtAPY6 和 AtAPY7 的功能分析。我们通过 qRT-PCR 和启动子：GUS 融合分析来分析 AtAPY6 和 7 表达的组织特异性。我们通过光镜和电子显微镜对 AtAPY6 和 7 的单突变体和双突变体在花药和花粉中的表型进行了表征。AtAPY6 和 7 的转录本都在成熟花粉粒中表达。AtAPY6 和 7 的单突变体在扫描电子显微镜下花粉外壁模式略有变化，但育性无明显变化。AtAPY6 和 7 的双突变体（apy6apy7）显示花粉外壁模式严重缺陷，花粉形状变形，雄性育性降低。对 apy6apy7 杂合子花粉的分析表明，花粉外壁的缺陷是由二倍体基因组决定的。我们的研究结果表明，AtAPY6 和 AtAPY7 是在花粉外壁发育中起重要作用的酶，可能通过调节关键多糖的产生来正确组装外壁层。
