Alexander Liza Esther, Winkelman Dirk, Stenback Kenna E, Lane Madison, Campbell Katelyn R, Trost Elysse, Flyckt Kayla, Schelling Michael A, Rizhsky Ludmila, Yandeau-Nelson Marna D, Nikolau Basil J
Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, United States.
Center for Metabolic Biology, Iowa State University, Ames, IA, United States.
Front Plant Sci. 2024 Jul 11;15:1403779. doi: 10.3389/fpls.2024.1403779. eCollection 2024.
The maize and genes are homologs, which encode proteins that belong to the BAHD family of acyltransferases. genetic studies have demonstrated that these genes may be involved in the elongation of very long chain fatty acids (VLCFAs) that are precursors of the cuticular wax fraction of the plant cuticle. VLCFAs are synthesized by a fatty acyl-CoA elongase complex (FAE) that consists of four component enzymes. Previously, we functionally identified the maize FAE component enzymes by their ability to complement haploid strains that carry lethal deletion alleles for each FAE component enzyme. In this study we used these complemented haploid strains and wild-type diploid strains to evaluate whether the co-expression of either GLOSSY2 or GLOSSY2-LIKE with individual maize FAE component enzymes affects the VLCFA product-profile of the FAE system. Wild-type diploid strains produced VLCFAs of up to 28-carbon chain length. Co-expression of GLOSSY2 or GLOSSY2-LIKE with a combination of maize 3-ketoacyl-CoA synthases stimulated the synthesis of longer VLCFAs, up to 30-carbon chain lengths. However, such results could not be recapitulated when these co-expression experiments were conducted in the yeast haploid mutant strains that lacked individual components of the endogenous FAE system. Specifically, lethal yeast mutant strains that are genetically complemented by the expression of maize FAE-component enzymes produce VLCFAs that range between 20- and 26-carbon chain lengths. However, expressing either GLOSSY2 or GLOSSY2-LIKE in these complemented strains does not enable the synthesis of longer chain VLCFAs. These results indicate that the apparent stimulatory role of GLOSSY2 or GLOSSY2-LIKE to enable the synthesis of longer chain VLCFAs in diploid yeast cells may be associated with mixing plant enzyme components with the endogenous FAE complex.
玉米和这些基因是同源物，它们编码属于BAHD酰基转移酶家族的蛋白质。遗传学研究表明，这些基因可能参与超长链脂肪酸（VLCFAs）的延长，超长链脂肪酸是植物角质层角质蜡质部分的前体。VLCFAs由一个由四种组成酶构成的脂肪酰辅酶A延长酶复合体（FAE）合成。此前，我们通过它们对携带每个FAE组成酶致死性缺失等位基因的单倍体菌株的互补能力，从功能上鉴定了玉米FAE组成酶。在本研究中，我们使用这些互补的单倍体菌株和野生型二倍体菌株来评估GLOSSY2或GLOSSY2-LIKE与单个玉米FAE组成酶的共表达是否会影响FAE系统的VLCFA产物谱。野生型二倍体菌株产生的VLCFAs碳链长度可达28。GLOSSY2或GLOSSY2-LIKE与玉米3-酮脂酰辅酶A合酶组合的共表达刺激了更长VLCFAs的合成，碳链长度可达30。然而，当在缺乏内源性FAE系统单个组分的酵母单倍体突变菌株中进行这些共表达实验时，无法重现这样的结果。具体而言，通过玉米FAE组分酶的表达进行基因互补的致死性酵母突变菌株产生的VLCFAs碳链长度在20至26之间。然而，在这些互补菌株中表达GLOSSY2或GLOSSY2-LIKE并不能使合成更长链的VLCFAs。这些结果表明，GLOSSY2或GLOSSY2-LIKE在二倍体酵母细胞中对合成更长链VLCFAs的明显刺激作用可能与将植物酶组分与内源性FAE复合体混合有关。
