Polyamine biosynthesis and control of the development of functional pollen in kiwifruit
Polyamine biosynthesis and control of the development of functional pollen in kiwifruit
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DOI：
10.1016/j.plaphy.2010.02.013
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发表时间：
2010-07-01
影响因子：
6.5
通讯作者：
Biasi, R.
中科院分区：
文献类型：
--
作者：
Falasca, G.;Franceschetti, M.;Biasi, R.
多胺(Pas)在植物生殖，特别是花粉发育和萌发中的作用已在几种高等植物中得到证实。本研究旨在探讨PA在猕猴桃雌雄异株花粉发育和萌发中的作用。在花粉发育(或雌花败育)过程中，PA含量、PA生物合成酶的水平和基因表达以及PA生物合成抑制剂的作用存在差异。而Pas，特别是亚精胺(Spd)，在功能花粉发育过程中一直保持较高水平，但在不育花粉发育的最后阶段，其水平下降。来自雄性可育花药的成熟和有功能的花粉在整个小配子发生过程中都显示出S腺苷蛋氨酸脱羧酶活性(SAMDC；参与Spd的生物合成)，从单核小孢子晚期开始就有高水平的可溶性SAMDC。不育花药中缺少可溶性SAMDC。精氨酸脱羧酶[ADC；用于腐胺(Put)生物合成]在功能花粉和不育花粉中几乎没有差异；鸟氨酸脱羧酶[ODC；也用于腐胺(Put)生物合成]只存在于不育花粉中。对雄性不育花败育花粉的超微结构研究表明，内壁附近的细胞质残留物含有小泡，向花粉壁挤出。败育的花粉壁残留物中有很高的SAMDC活性。将竞争性抑制剂S-腺苷蛋氨酸脱羧酶(MGBG)和亚精胺合成酶(CHA)或D-精氨酸(Put合成抑制剂)联合应用于雄性可育植株，可导致花粉粒异常，存活率降低。事实上，PA生物合成酶(ADC和主要是SAMDC)在花粉水合和萌发的早期就处于活跃状态。两种不同的SAMDC基因转录本在萌发的花粉中表达，同时有较低水平的ADC转录本表达。基因表达先于PA酶活性。PA抑制剂在猕猴桃花粉萌发中的应用大大减少了花粉萌发，因此，低游离Spd会导致猕猴桃花粉粒退化或功能丧失。(C)2010年爱思唯尔·马森公司。版权所有。
The role of polyamines (PAs) in plant reproduction, especially pollen development and germination has been demonstrated in several higher plants. The aim of the present research was to investigate PA involvement in pollen development and germination in dioecious kiwifruit (Actinidia deliciosa). Differences in PA content, level and gene expression for PA biosynthetic enzymes, and the effect of PA biosynthetic inhibitors were found during pollen development (or abortion in female flowers). Whereas PAs, especially spermidine (Spd), remained high throughout the development of functional pollen, the levels collapsed by the last stage of development of sterile pollen. Mature and functional pollen from male-fertile anthers showed S-adenosyl methionine decarboxylase activity (SAMDC; involved in Spd biosynthesis) throughout microgametogenesis, with high levels of soluble SAMDC found starting from the late uninucleate microspore stage. Soluble SAMDC was absent in male-sterile anthers. Arginine decarboxylase [ADC; for putrescine (Put) biosynthesis] showed little difference in functional vs sterile pollen; ornithine decarboxylase [ODC; also for putrescine (Put) biosynthesis] was present only in sterile pollen. Ultrastructural studies of aborted pollen grains in male-sterile flowers showed that cytoplasmic residues near the intine contain vesicles, extruding towards the pollen wall. Very high SAMDC activity was found in the wall residues of the aborted pollen. The combined application in planta of competitive inhibitors of S-adenosylmethionine decarboxylase (MGBG) and of spermidine synthase (CHA), or of D-arginine (inhibitor of Put synthesis), to male-fertile plants led to abnormal pollen grains with reduced viability.The importance of PAs during male-fertile pollen germination was also found. In fact, PA biosynthetic enzymes (ADC and, mainly, SAMDC) were active early during pollen hydration and germination in vitro. Two different SAMDC gene transcripts were expressed in germinating pollen together with a lower level of ADC transcript. Gene expression preceded PA enzyme activity. The application of PA inhibitors in planta drastically reduced pollen germination.Thus, low free Spd can lead either to degeneration or loss of functionality of kiwifruit pollen grains. (C) 2010 Elsevier Masson SAS. All rights reserved.