Glagoleva Anastasiya Y, Shmakov Nikolay A, Shoeva Olesya Y, Vasiliev Gennady V, Shatskaya Natalia V, Börner Andreas, Afonnikov Dmitry A, Khlestkina Elena K
Institute of Cytology and Genetics SB RAS, Novosibirsk, Russia.
Novosibirsk State University, Novosibirsk, Russia.
BMC Plant Biol. 2017 Nov 14;17(Suppl 1):182. doi: 10.1186/s12870-017-1124-1.
Some plant species have 'melanin-like' black seed pigmentation. However, the chemical and genetic nature of this 'melanin-like' black pigment have not yet been fully explored due to its complex structure and ability to withstand almost all solvents. Nevertheless, identification of genetic networks participating in trait formation is key to understanding metabolic processes involved in the expression of 'melanin-like' black seed pigmentation. The aim of the current study was to identify differentially expressed genes (DEGs) in barley near-isogenic lines (NILs) differing by allelic state of the Blp (black lemma and pericarp) locus.
RNA-seq analysis of six libraries (three replicates for each line) was performed. A total of 957 genome fragments had statistically significant changes in expression levels between lines BLP and BW, with 632 fragments having increased expression levels in line BLP and 325 genome fragments having decreased expression. Among identified DEGs, 191 genes were recognized as participating in known pathways. Among these were metabolic pathways including 'suberin monomer biosynthesis', 'diterpene phytoalexins precursors biosynthesis', 'cutin biosynthesis', 'cuticular wax biosynthesis', and 'phenylpropanoid biosynthesis, initial reactions'. Differential expression was confirmed by real-time PCR analysis of selected genes.
Metabolic pathways and genes presumably associated with black lemma and pericarp colour as well as Blp-associated resistance to oxidative stress and pathogens, were revealed. We suggest that the black pigmentation of lemmas and pericarps is related to increased level of phenolic compounds and their oxidation. The effect of functional Blp on the synthesis of ferulic acid and other phenolic compounds can explain the increased antioxidant capacity and biotic and abiotic stress tolerance of black-grained cereals. Their drought tolerance and resistance to diseases affecting the spike may also be related to cuticular wax biosynthesis. In addition, upregulated synthesis of phytoalexins, suberin and universal stress protein (USP) in lemmas and pericarps of the Blp carriers may contribute to their increased disease resistance. Further description of the DEGs haplotypes and study of their association with physiological characteristics may be useful for future application in barley pre-breeding.
一些植物物种具有“黑色素样”黑色种子色素沉着。然而，由于这种“黑色素样”黑色色素的结构复杂且几乎能耐受所有溶剂，其化学和遗传本质尚未得到充分探索。尽管如此，鉴定参与性状形成的遗传网络是理解“黑色素样”黑色种子色素沉着表达所涉及代谢过程的关键。本研究的目的是在大麦近等基因系（NILs）中鉴定因Blp（黑色颖壳和果皮）位点等位基因状态不同而差异表达的基因（DEGs）。
对六个文库（每个品系三个重复）进行了RNA测序分析。共有957个基因组片段在BLP和BW品系之间的表达水平有统计学显著变化，其中632个片段在BLP品系中表达水平升高，325个基因组片段表达下降。在鉴定出的DEGs中，191个基因被认为参与已知途径。其中包括代谢途径，如“木栓质单体生物合成”、“二萜植保素前体生物合成”、“角质生物合成”、“表皮蜡质生物合成”和“苯丙烷类生物合成，初始反应”。通过对选定基因的实时PCR分析证实了差异表达。
揭示了可能与黑色颖壳和果皮颜色以及与Blp相关的对氧化应激和病原体的抗性相关的代谢途径和基因。我们认为颖壳和果皮的黑色色素沉着与酚类化合物水平的增加及其氧化有关。功能性Blp对阿魏酸和其他酚类化合物合成的影响可以解释黑粒谷物抗氧化能力以及生物和非生物胁迫耐受性的增加。它们的耐旱性和对影响穗部疾病的抗性也可能与表皮蜡质生物合成有关。此外，Blp携带者的颖壳和果皮中植保素、木栓质和通用应激蛋白（USP）的合成上调可能有助于其抗病性增强。对DEGs单倍型的进一步描述及其与生理特征的关联研究可能对未来在大麦预育种中的应用有用。
