外源硫酸铝调节八仙花花青苷组成和含量变化的分子生物学机制

Mechanism of exogenous Al_2(SO_4)_3 on regulating the anthocyanin concentration in Hydrangea macrophylla petal

【目的】八仙花是我国重要的观赏植物之一,本研究旨在探讨Al_2(SO_4)_3对八仙花花色的影响及其机制。【方法】以‘蓝色妈妈’品种为对象进行盆栽试验,设置了0(p H为6的柠檬酸缓冲液)、2‰和4‰3个Al_2(SO_4)_3水平,在植株出现花蕾约1 cm时进行处理。在开花盛期进行花色分析,采用高效液相色谱法和质谱分析花青苷成分和含量,采用电感耦合等离子体原子发射光谱法分析金属离子含量,采用荧光定量PCR分析Al^(3+)运输相关基因表达水平。【结果】2‰和4‰的Al_2(SO_4)_3处理21 d后,花瓣颜色从粉色变为紫色和蓝紫色。‘蓝色妈妈’花瓣中检测到了飞燕草素-3-葡萄糖苷等12种花青苷;2‰和4‰的Al_2(SO_4)_3处理显著(P<0.05)增加了飞燕草素苷、矢车菊素苷和芍药花素苷含量,其中增加幅度最大的是飞燕草素苷含量,从对照(CK)组的5159.9μg/g FW分别增加到24681.2μg/g FW和30485.7μg/g FW;飞燕草素苷含量增加主要是由于飞燕草素-3-葡萄糖苷和飞燕草素-3-戊糖-5-葡萄糖苷含量增加,飞燕草素-3-葡萄糖苷含量从对照的4679.2μg/g FW分别增加到23610.0μg/g FW和29129.7μg/g FW,飞燕草素-3-戊糖-5-葡萄糖苷从对照的142.3μg/g FW分别增加到805.6μg/g FW和1114.9μg/g FW。2‰和4‰的Al_2(SO_4)_3处理后,花瓣中Al^(3+)含量从对照的2.24μg/g FW分别增加到5.12μg/g FW和11.83μg/g FW;2‰和4‰的Al_2(SO_4)_3处理后,花瓣中质膜铝转运基因(plasma membrane Al transporter,PALT)和液泡膜铝转运基因(vacuolar Al transporter,VALT)表达水平显著提高(P<0.05),PALT表达水平分别比对照提高了88.5%和148.2%,VALT表达水平分别比对照提高了74.8%和135.7%。【结论】Al_2(SO_4)_3处理诱导了Al^(3+)运输相关基因的表达,增加了花瓣中Al^(3+)积累,提高了飞燕草素苷含量,进而改变了花的颜色。

[ Objectives ] Hydrangea macrophylla is one of the most important ornamental plants. The present paper aimed to study effects 0fA12（SO4）3 on flower colour of Hydrangea macrophylla. [ Methods ] Hydrangea macrophylla cultivar ＇mama blue＇ was selected as material, and a pot experiment was conducted by setting up two Al2（SO4）3 concentration levels, 2%0 and 4%0. Al2（SO4）3 was added into the growth media when the flower bud was about 1 cm length, and citrate buffer （pH 6.0） was added in control plants. The composition and concentrations of anthocyanins were determined by HPLC and mass spectrometry, ion concentrations were measured by ICP-AES, and expression of A13＋ transport related genes was clarified by qRT-PCR. [ Results ] The petal colour changed from pink to purple and blue-purple after 21 d by the 2‰ and 4‰ Al2（SO4）3 application, respectively. Twelve kinds of anthocyanins, such as delphinidin 3-glucoside, were detected in the petal. The A12（SO4）3 treatments increased the anthocyanins contents, especially the delphinidinderivatives contents. The delphinidinderivatives contents in petals were increased from 5159.9 μg/g FW in control plants to 24681.2 μg/g FW and 30485.7 μg/g FW in 2‰ and 4‰ Al2（SO4）3 treated plants, respectively. The increase of delphinidin derivatives contents was due to the enhancement of delphinidin 3-glucoside and delphinidin 3- pentose-5-glucoside.The delphinidin 3-glucoside contents in petals were increased from 4679.2 μg/g FW in control plants to 23610.0 μg/g FW and 29129.7μg/g FW in 2%o and 4%o A12（SO4）3 treated plants, respectively, and the contents of delphinidin 3-pentose-5-glucoside in petals were increased from 142.3 μg/g FW in control plants to 805.6 μg/g FW and 1114.9 μg/g FW in 2‰ and 4‰ Al2（SO4）3 treated plants, respectively. And the A13＋ contents in petals were increased from 2.24 μg/g FW in control plants to 5.12 μg/g FW and 11.83 μg/g FW in 2‰ and 4‰ Al2（SO4）3 treated plants, respectively. Accordingly, the gene expression of vacuolar Al transporter （VALT） and plasma membrane Al transporter （PALT） were increased significantly （P 〈 0.05） by the Al2（SO4）3 application. Compared with control plants, the PALT expression levels were increased by 88.5% and 148.2% in 2‰ and 4‰ Al2（NO4）3 treated plants, respectively, and the VALT expression levels were increased by 74.8% and 135.7%. [ Conclusions ] Our results suggested that Al2（SO4）3 application induced the gene expression of VALT and PALT, enhanced the accumulation of AP, increased the delphinidinderivatives contents, and thus changed the flower colour from pink to purple and blue-purple.