Kernel hardness is an important agronomic trait that influences end-product properties. In wheat cultivars, this trait is determined by thePuroindoline a (Pina) andPuroindoline b (Pinb) genes, located in theHardness locus (Ha) on chromosome 5DS of the D genome. Wild type alleles code puroindoline a (PINA) and puroindoline b (PINB) proteins, which form a 15-kDa friabilin present on the surface of water-washed starch granules. Both the proteins are accumulated in the starch endosperm cells and aleurone of the mature kernels.Puroindoline-like genes coding puroindoline-like proteins in the starch endosperm occur in some of the genomes of Triticeae and Aveneae cereals. Orthologs are present in barley, rye and oats. However, some genomes of these diploid and polyploid cereals, like that ofTriticum turgidum var.durum (AABB) lack thepuroindoline genes, having a very hard kernel texture. The two wild type alleles in opposition (dominant loci) control the soft pheno-type. Mutation either inPina orPinb or in both leads to a medium-hard or hard kernel texture. The most frequent types ofPin mutations are point mutations within the coding sequence resulting in the substitution of a single amino acid or a null allele. The latter is the result of a frame shift determined by base deletion or insertion or a one-point mutation to the stop codon. The lipid-binding properties of the puroindolines affect not only the dough quality but also the plants’ resistance to pathogens. Genetic modification of cereals withPuroindoline genes and/or their promoters enable more detailed functional analyses and the production of plants with the desired characteristics.

中文翻译：

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谷物中谷物质地的决定因素。

籽粒硬度是影响最终产品特性的重要农艺性状。在小麦品种中，该性状由位于D 基因组染色体 5DS 上的硬度基因座 ( Ha ) 中的Puroindoline a (Pina)和Puroindoline b (Pinb)基因决定。野生型等位基因编码嘌呤二氢吲哚 a (PINA) 和嘌呤二氢吲哚 b (PINB) 蛋白，它们形成存在于水洗淀粉颗粒表面的 15-kDa 脆性蛋白。这两种蛋白质都在淀粉胚乳细胞和成熟谷粒的糊粉中积累。嘌呤二氢吲哚淀粉胚乳中编码嘌呤二氢吲哚样蛋白的 β-样基因出现在小麦科和燕麦科谷物的一些基因组中。直向同源物存在于大麦、黑麦和燕麦中。然而，这些二倍体和多倍体谷物的一些基因组，如Triticum turgidum var. durum (AABB) 缺乏嘌呤二氢吲哚基因，具有非常坚硬的内核质地。两个相对的野生型等位基因（优势位点）控制软表型。Pina或Pinb或两者中的突变导致中硬或硬核质地。最常见的Pin类型突变是编码序列内的点突变，导致单个氨基酸或无效等位基因的取代。后者是由碱基缺失或插入或终止密码子的单点突变决定的移码结果。嘌呤二氢吲哚的脂质结合特性不仅会影响面团质量，还会影响植物对病原体的抵抗力。用嘌呤二氢吲哚基因和/或其启动子对谷物进行遗传修饰，可以进行更详细的功能分析和生产具有所需特征的植物。