Campbell S A, Crone D E, Ceccardi T L, Close T J
Department of Botany and Plant Sciences, University of California, Riverside 92521-0124, USA.
Plant Mol Biol. 1998 Oct;38(3):417-23. doi: 10.1023/a:1006037308167.
Dehydrins (LEA D11 proteins) are the products of multigene families in a number of higher plants. To date, however, only one dehydrin locus, dhn1 (a major embryo and drought-induced protein of ca. 18 kDa) has been placed on chromosome 6L of the genetic linkage map of maize. The presence of a larger, ca. 40 kDa embryo protein that is also specifically detected by anti-dehydrin antibodies had been observed in some maize inbreds, including B73, suggesting that other dhn loci may exist. The ca. 22 kDa and ca. 40 kDa immunopositive proteins were purified from B73 and their amino acid compositions determined. The two proteins' amino acid compositions are typical of dehydrins, yet they differ from each other, indicating that they are distinct dhn gene products. Different size alleles for both proteins, or presence/absence in the case of the ca. 40 kDa protein, were evident from comparisons of embryo proteins of various maize inbreds. Analysis of segregating F2 progeny derived from self-pollination of F1 hybrids from four crosses (B73 x OH43, Mo17 x A632, AHO x A632, Latente x A632) revealed that alleles of the two genes assort independently. Map positions of the two dhn loci were then determined using two maize recombinant inbred line (RIL) mapping populations. The predicted map position of the gene controlling production of the ca. 22 kDa protein confirmed that this protein is the product of the dhn1 gene. The gene encoding the ca. 40 kDa dehydrin-like protein maps to a new locus on chromosome 9S near wx1, which we have named dhn2.
脱水素（胚胎发育晚期丰富蛋白D11）是许多高等植物中多基因家族的产物。然而，到目前为止，在玉米的遗传连锁图谱上，仅一个脱水素基因座dhn1（一种约18 kDa的主要胚胎和干旱诱导蛋白）被定位在第6L染色体上。在包括B73在内的一些玉米自交系中，观察到一种更大的、约40 kDa的胚胎蛋白，该蛋白也能被抗脱水素抗体特异性检测到，这表明可能存在其他dhn基因座。从B73中纯化出了约22 kDa和约40 kDa的免疫阳性蛋白，并测定了它们的氨基酸组成。这两种蛋白的氨基酸组成是脱水素的典型特征，但彼此不同，表明它们是不同的dhn基因产物。通过比较各种玉米自交系的胚胎蛋白，明显发现这两种蛋白都存在不同大小的等位基因，对于约40 kDa的蛋白则存在有无差异。对四个杂交组合（B73×OH43、Mo17×A632、AHO×A632、Latente×A632）的F1杂种自交产生的分离F2后代进行分析，结果显示这两个基因的等位基因独立分离。然后利用两个玉米重组自交系（RIL）作图群体确定了两个dhn基因座的图谱位置。预测控制约22 kDa蛋白产生的基因的图谱位置证实该蛋白是dhn1基因的产物。编码约40 kDa脱水素样蛋白的基因定位到第9S染色体上靠近wx1的一个新基因座，我们将其命名为dhn2。
