Characterization of cDNAs associated with lignification and their expression profiles in loquat fruit with different lignin accumulation
Characterization of cDNAs associated with lignification and their expression profiles in loquat fruit with different lignin accumulation
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不同木质素积累枇杷果实木质化相关cDNA的表征及其表达谱
DOI：
10.1007/s00425-008-0696-2
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发表时间：
2008-05-01
期刊：
影响因子：
4.3
通讯作者：
Chen, Kun Song
中科院分区：
文献类型：
--
作者：
Shan, Lan Lan;Li, Xian;Chen, Kun Song
具有不同木质素积累水平的两个枇杷（EriobotryajaponicaLindl.）品种的成熟果实提供了果肉组织中木质化的有趣例子。成熟的红肉洛阳青（LYQ）果实由于木质化而硬度增加，而白肉白沙（BS）果实在没有木质化的情况下软化。与木质化途径相关的 6 个 cDNA，即 EjPAL1、EjPAL2（苯丙氨酸解氨酶，PAL，EC 4.3.1.5）、Ej4CL（4-香豆酸：辅酶 A 连接酶，4CL，EC 6.2.1.12）、EjCAD1、EjCAD2（肉桂醇脱氢酶，CAD、EC） 1.1.1.195）和EjPOD（过氧化物酶，POD），是从LYQ果实的肉组织中克隆出来的。在LYQ和BS品种的不同组织以及果实发育和成熟过程中，六个相应基因的表达谱差异很大。还测量了 PAL、4CL、CAD 和 POD 酶的相关活性。 CAD和POD酶活性以及EjCAD1和EjPOD基因的表达在时间上与枇杷果肉组织的木质化关系最为密切。 EjCAD1 转录本的水平与成熟过程中木质化的变化特别一致，通过乙烯处理或低温调节进行修改。两个PAL基因在果实发育过程中表现出不同的表达模式，其中EjPAL1在成熟果实中强烈表达，而EjPAL2仅在发育早期表达。此外，EjCAD1表达受低温刺激，可能导致果实低温损伤。我们关于木质素、木质素单体前体以及相关酶和基因的综合数据提供了水果木质化的一致模型。
The ripening fruit of two loquat (EriobotryajaponicaLindl.) cultivars with different levels of lignin accumulation provide an intriguing example of lignification in flesh tissue. Increase in firmness as a result of lignification in ripening red-fleshed Luoyangqing (LYQ) fruit was confirmed, whereas white-fleshed Baisha (BS) fruit softened without lignification. Six cDNAs associated with the lignification pathway, i.e.EjPAL1,EjPAL2(phenylalanine ammonia lyase, PAL, EC 4.3.1.5),Ej4CL(4-coumarate: coenzyme A ligase, 4CL, EC 6.2.1.12),EjCAD1,EjCAD2(cinnamyl alcohol dehydrogenase, CAD, EC 1.1.1.195) andEjPOD(peroxidase, POD), were cloned from flesh tissue of LYQ fruit. Expression profiles of the six corresponding genes differed greatly in different tissues, and during fruit development and ripening in both LYQ and BS cultivars. Associated activities of PAL, 4CL, CAD, and POD enzymes were also measured. CAD and POD enzyme activities and the expression ofEjCAD1andEjPODgenes were most closely associated temporally with lignification of loquat flesh tissue. Levels ofEjCAD1transcripts were particularly aligned with changes in lignification during ripening as modified either by ethylene treatment or low temperature conditioning. The two PAL genes showed different expression patterns during fruit development, withEjPAL1strongly expressed in mature fruit andEjPAL2only expressed in early stages of development. In addition,EjCAD1expression was stimulated by low temperature and may contribute to low temperature injury in the fruit. Our integrated data on lignin, monolignol precursors, and associated enzymes and genes, provide a consistent model of fruit lignification.