Analysis of the aliphatic monomer composition of polyesters associated with Arabidopsis epidermis:: occurrence of octadeca-cis-6, cis-9-diene-1,18-dioate as the major component
Analysis of the aliphatic monomer composition of polyesters associated with Arabidopsis epidermis:: occurrence of octadeca-cis-6, cis-9-diene-1,18-dioate as the major component
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DOI：
10.1111/j.1365-313x.2004.02258.x
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发表时间：
2004-12-01
期刊：
影响因子：
7.2
通讯作者：
Pollard, M
中科院分区：
文献类型：
--
作者：
Bonaventure, G;Beisson, F;Pollard, M
虽然拟南芥叶和茎的表面蜡质已经得到了彻底的表征，但角质层膜聚酯的单体组成还没有被分析。脱脂后的拟南芥叶或茎在裂解聚酯的条件下进行解聚，生成典型的欧米伽-羟基脂肪酸角质蛋白单体，如16-羟基-棕榈酸酯、10，16-二羟基-棕榈酸酯和18-羟基-9，10-环氧硬脂酸酯。但主要单体为顺-6，顺-9-二烯-1，18-二酸十八酯，少量的顺-顺-9-烯-1，18-二酸十八酯和十六碳-1，16-二酸十八酯。这些二羧酸盐主要存在于拟南芥茎的表皮中，因此很可能与角质膜有关。在油菜叶的分析中也发现了它们，但在番茄和苹果的水果切条中没有。在拟南芥fad2-1突变系中，细胞质磷脂中亚油酸和亚麻酸的含量降低，油酸含量升高，十八碳-顺-6，顺-9-二烯-1，18-二酸的含量减少50%，而十八碳-顺-9-烯-1，18-二酸的含量增加。在拟南芥的FatB-Ko系中，胞质棕榈酸酯的可获得性受到损害，C-16单体损失了80%，C-18单体补偿性增加。角质膜中存在大量的二羧酸盐是意想不到的。大量的脂族二羧酸盐通常被认为是Suberin的指示物，并且只被报道为角质的非常微小的成分。角质层中高水平的多不饱和也是不寻常的；饱和脂肪酸单体通常占主导地位，单不饱和脂肪酸含量较少。这些针对拟南芥的新发现表明，表皮的聚酯可以有很大范围的单体组成。
Although the surface waxes from Arabidopsis thaliana leaves and stems have been thoroughly characterized, the monomer composition of the polyesters of the cuticular membrane has not been analyzed. Delipidated Arabidopsis leaves or stems, when depolymerized under conditions to cleave polyesters, produced typical omega-hydroxy fatty acid cutin monomers such as 16-hydroxy-palmitate, 10,16-dihydroxy-palmitate and 18-hydroxy-9,10-epoxy-stearate. However, the major monomer was octadeca-cis-6, cis-9-diene-1,18-dioate, with lesser amounts of octadec-cis-9-ene-1,18-dioate and hexadeca-1,16-dioate. These dicarboxylates were found predominantly in epidermal peels from Arabidopsis stems and are therefore likely to be associated with the cuticular membrane. They were also found in analyses of canola leaves but were absent in tomato and apple fruit cutins. In the fad2-1 mutant line of Arabidopsis, which has reduced levels of linoleate and linolenate and elevated oleate in cytosolic phospholipids, the amount of octadeca-cis-6, cis-9-diene-1,18-dioate was 50% reduced, with a concomitant increase in octadec-cis-9-ene-1,18-dioate. In a fatb-ko line of Arabidopsis, where the availability of cytosolic palmitate is impaired, there was an 80% loss of C-16 monomers and a compensating increase in C-18 monomers. The presence of substantial amounts of dicarboxylates in cuticular membranes is unexpected. High amounts of aliphatic dicarboxylates are usually considered as an indicator of suberin, and are reported only as very minor components of cutin. The high level of polyunsaturation is also unusual in cuticles; saturated fatty acid monomers usually predominate, with lesser amounts of monounsaturates. These novel findings for Arabidopsis demonstrate that a broad range of monomer compositions are possible for polyesters of the epidermis.