Patatin-related phospholipase A (pPLA) hydrolyses glycerolipids to produce fatty acids and lysoglycerolipids. The Oryza sativa genome has 21 putative pPLAs that are grouped into five subfamilies. Overexpression of OspPLAIIIα resulted in a dwarf phenotype with decreased length of rice stems, roots, leaves, seeds, panicles, and seeds, whereas OspPLAIIIα-knockout plants had longer panicles and seeds. OspPLAIIIα-overexpressing plants were less sensitive than wild-type and knockout plants to gibberellin-promoted seedling elongation. OspPLAIIIα overexpression and knockout had an opposite effect on the expression of the growth repressor SLENDER1 in the gibberellin signalling process. OspPLAIIIα-overexpressing plants had decreased mechanical strength and cellulose content, but exhibited increases in the expression of several cellulose synthase genes. These results indicate that OspPLAIIIα plays a role in rice vegetative and reproductive growth and that the constitutive, high activity of OspPLAIIIα suppresses cell elongation. The decreased gibberellin response in overexpressing plants is probably a result of the decreased ability to make cellulose for anisotropic cell expansion.
馬鈴薯糖蛋白相關(guān)磷脂酶A（pPLA）水解甘油酯，進(jìn)而產(chǎn)生脂肪酸和溶血甘油酯。水稻基因組包含21個推測的pPLAs，分為5個亞家族。過表達(dá)OspPLAIIIα會引起半矮化表型，同時水稻莖、根、葉、種子以及穗的長度均降低，而OspPLAIIIα敲除植株具有更長的穗和種子。與野生型和敲除植株相比，OspPLAIIIα過表達(dá)植株對赤霉素促進(jìn)幼苗的伸長作用不敏感。過表達(dá)和敲除OspPLAIIIα對赤霉素信號過程中生長抑制因子SLENDER1的表達(dá)具有相反的作用。OspPLAIIIα過表達(dá)植株機(jī)械強(qiáng)度和纖維素含量降低，但表現(xiàn)出一些纖維素合成酶基因的表達(dá)增加。這些結(jié)果表明，OspPLAIIIα在水稻營養(yǎng)生長和生殖生長中發(fā)揮重要作用，OspPLAIIIα的組成性高活性會抑制細(xì)胞伸長。過表達(dá)植株中赤霉素響應(yīng)降低可能是由于影響非勻質(zhì)性細(xì)胞膨大的纖維素合成能力降低導(dǎo)致的。