Nicholas C D, Lindstrom J T, Vodkin L O
Department of Agronomy, University of Illinois, Urbana 61801.
Plant Mol Biol. 1993 Jan;21(1):145-56. doi: 10.1007/BF00039625.
The I locus controls inhibition of anthocyanin accumulation in the epidermal cells of the soybean seed coat and affects abundance of PRP1, a proline-rich cell wall protein in the seed coat. Saline-soluble PRP1 is abundant in the developing seed coats of cultivar Richland (homozygous I, yellow), while it is significantly decreased in the pigmented isogenic mutant T157 (homozygous i, imperfect black). In this report, we examined soluble PRP1 in several cultivars containing alleles of the I locus which affect spatial distribution of pigmentation in the seed coat. We also characterized PRP1 in isolines with allelic variants of several other loci involved in seed coat pigmentation, including T and Im. The T gene is pleiotropic and affects both pubesence color and seed coat pigmentation and structure. Soluble PRP1 was abundant in the developing seed coats of lines with yellow seed (I or ii alleles) regardless of pubescence color, just as in Richland. Likewise, soluble PRP1 was decreased in pigmented seed coats (ik or i alleles) with grey (t) pubescence, as in T157. However, the total seed coat proteins were not extractable from pigmented seed coats with tawny pubescence (i, T genotypes) because they have proanthocyanidins that exhibit tannin properties. The dominant Im allele inhibits seed coat mottling (irregular patches of pigmentation) that occurs if plants are infected with soybean mosaic virus. PRP1 was 35 kDa in mottled (im) isolines and 34 kDa in non-mottled (Im) isolines. PRP2, which is expressed later in seed coat development and in the hypocotyl hooks of soybean seedlings, was also smaller in Im isolines. In summary, some of the anthocyanin mutations affect the quantity of soluble PRP1 polypeptides. while others correlate with structural changes in developmentally regulated proline-rich proteins.
I基因座控制大豆种皮表皮细胞中花青素积累的抑制，并影响PRP1的丰度，PRP1是种皮中一种富含脯氨酸的细胞壁蛋白。盐溶性PRP1在品种Richland（纯合I，黄色）发育中的种皮中含量丰富，而在有色同基因突变体T157（纯合i，不完全黑色）中显著减少。在本报告中，我们检测了几个含有I基因座等位基因的品种中可溶性PRP1，这些等位基因影响种皮色素沉着的空间分布。我们还对与种皮色素沉着相关的其他几个基因座的等位基因变体的近等基因系中的PRP1进行了表征，包括T和Im。T基因具有多效性，影响茸毛色和种皮色素沉着及结构。与Richland一样，无论茸毛色如何，黄色种子（I或ii等位基因）品系发育中的种皮中可溶性PRP1含量丰富。同样，与T157一样，灰色（t）茸毛的有色种皮（ik或i等位基因）中可溶性PRP1减少。然而，黄褐色茸毛（i，T基因型）的有色种皮中无法提取总种皮蛋白，因为它们含有具有单宁特性的原花青素。显性Im等位基因抑制种皮斑驳（色素沉着不规则斑块），如果植物感染大豆花叶病毒就会出现这种情况。斑驳（im）近等基因系中PRP1为35 kDa，非斑驳（Im）近等基因系中PRP1为34 kDa。PRP2在种皮发育后期和大豆幼苗的下胚轴钩中表达，在Im近等基因系中也较小。总之，一些花青素突变影响可溶性PRP1多肽的数量，而其他突变与发育调控的富含脯氨酸的蛋白质的结构变化相关。
