Molecular and physiological dissection of enhanced seed germination using short-term low-concentration salt seed priming in tomato
Molecular and physiological dissection of enhanced seed germination using short-term low-concentration salt seed priming in tomato
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DOI：
10.1016/j.plaphy.2011.11.005
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发表时间：
2012-03-01
影响因子：
6.5
通讯作者：
Ezura, Hiroshi
中科院分区：
文献类型：
--
作者：
Nakaune, Makoto;Hanada, Atsushi;Ezura, Hiroshi
种子萌发是植物发育的第一步。盐对番茄种子萌发的促进作用然而，通过启动提高种子萌发的分子和生理机制仍有待阐明。在本研究中，我们检测了种子在启动处理期间和之后的以下变化：内源脱落酸（ABA）和赤霉素（GA）浓度；8′-羟化酶（CYP707A）、共丙二磷酸合成酶（CPS）、GA20 -氧化酶（GA20ox）和GA3 -氧化酶（GA3ox）等ABA分解代谢酶和GA生物合成酶基因的表达；和胚乳帽弱化酶，包括扩张蛋白（EXP）、ⅰ类β -1,3-葡聚糖酶（GulB）、β -甘露聚糖内切酶（MAN）和木葡聚糖内切转葡萄糖酶（XTH）。将番茄种子在300 mM NaCl （NaCl-priming）或蒸馏水（hydro-priming）中25℃下黑暗浸泡24 h。两种处理的种子ABA含量均在处理期间升高，播后迅速下降。在启动处理期间和启动处理后，水启动种子和nacl启动种子中ABA含量无显著差异。SIGA20ox1、SIGA3ox1和SIGA3ox2在nacl引物种子中的表达量明显高于氢引物种子。两种引物处理后的GA(4)含量均可量化，表明GA(4)是参与番茄种子萌发的主要生物活性GA分子。播后12 h及以后，nacl处理种子GA(4)含量显著高于水处理种子。此外，SIEXP4、SIGulB、SIMAN2和SIXTH4的峰值表达水平在nacl引物种子中出现得更早，且显著高于氢引物种子。这些结果表明，nacl对番茄种子萌发的影响是通过激活GA(4)生物合成基因来增加GA(4)含量，从而增加胚乳帽弱化相关基因的表达。(C) 2011 Elsevier Masson SAS。版权所有。
Seed germination is the initial step of plant development. Seed priming with salt promotes seed germination in tomato (Solanum lycopersicum L.); however, the molecular and physiological mechanisms underlying the enhancement of seed germination by priming remain to be elucidated. In this study, we examined the following in seeds both during and after priming treatment: the endogenous abscisic acid (ABA) and gibberellin (GA) concentrations; the expression of genes encoding ABA catabolic and GA biosynthesis enzymes, including 8'-hydroxylase (CYP707A), copalyl diphosphate synthase (CPS), GA 20-oxidase (GA20ox) and GA 3-oxidase (GA3ox); and endosperm cap weakening enzymes, including expansin (EXP), class I beta-1,3-glucanase (GulB), endo-beta-mannanase (MAN) and xyloglucan endo-transglucosylase (XTH). Tomato seeds were soaked for 24 h at 25 degrees C in the dark in 300 mM NaCl (NaCl-priming) or distilled water (hydro-priming). For both priming treatments, the ABA content in the seeds increased during treatment but rapidly decreased after sowing. Both during and after the priming treatments, the ABA levels in the hydro-primed seeds and NaCl-primed seeds were not significantly different. The expression levels of SIGA20ox1, SIGA3ox1 and SIGA3ox2 were significantly enhanced in the NaCl-primed seeds compared to the hydro-primed seeds. The GA(4) content was quantifiable after both types of priming, indicating that GA(4) is the major bioactive GA molecule involved in tomato seed germination. The GA(4) content was significantly higher in the NaCl-primed seeds than in the hydro-primed seeds 12 h after sowing and thereafter. Additionally, the peak expression levels of SIEXP4, SIGulB, SIMAN2 and SIXTH4 occurred earlier and were significantly higher in the NaCl-primed seeds than in the hydro-primed seeds. These results suggest that the observed effect of NaCl-priming on tomato seed germination is caused by an increase of the GA(4) content via GA biosynthetic gene activation and a subsequent increase in the expression of genes related to endosperm cap weakening. (C) 2011 Elsevier Masson SAS. All rights reserved.