结瘤素基因主要参与豆科植物根瘤的形成。非结瘤植物中也存在类结瘤素基因, 主要调控植物的生长发育。MtN21 (Medicago truncatula NODULIN 21)基因家族属于类结瘤素基因家族, 仅少数成员已被鉴定。以拟南芥(Arabidopsis thaliana) MtN21家族为参考, 对棉花(Gossypium hirsutum) MtN21基因家族进行了生物信息学分析, 发现棉花与拟南芥的 MtN21基因同源性较高, 有共同的跨膜结构域EamA和PLN00411; 棉花中仅含PLN00411结构域的MtN21蛋白等电点低于含EamA结构域的蛋白; 亚细胞定位主要在质膜、液泡膜和叶绿体, 少数在细胞核; MtN21蛋白具有膜内侧的磷酸化位点。研究结果表明, 棉花MtN21为跨膜蛋白, 具有转运活性, 可能在棉花生长发育和病原体免疫方面发挥一定的作用。

Nodulin genes are involved in nodulation in leguminous species. Nodulin-like genes are also found in non-nodulating species, playing important roles during plant development. The Medicago truncatula NODULIN 21 (MtN21) family is one member of the nodulin-like gene family. However, only a few MtN21-like genes have been characterized. We compared MtN21-like genes in cotton with MtN21-like genes in Arabidopsis by bioinformatics methods. MtN21-like genes in cotton are homologous to those in Arabidopsis. MtN21-like proteins in cotton and Arabidopsis both have the same transmembrane domains, such as EamA and PLN00411. In cotton, the isoelectric points are predicted to be lower in MtN21-like proteins containing only the PLN00411 domain than those of MtN21-like proteins containing the EamA domain. The MtN21-like proteins are predicted to localize to the plasma membrane, tonoplast, chloroplast or nucleus in cotton. MtN21-like proteins in cotton have phosphorylation sites in the cytoplasmic portion of membrane. MtN21-like proteins in cotton may be transmembrane proteins with transporter activities. They may play roles in development and defense against pathogens in cotton.