Goormachtig S, Lievens S, Van de Velde W, Van Montagu M, Holsters M
Laboratorium voor Genetica, Department of Genetics, Flanders Interuniversity Institute for Biotechnology, Universiteit Gent, K.L. Ledeganckstraat 35, B-9000 Gent, Belgium.
Plant Cell. 1998 Jun;10(6):905-15. doi: 10.1105/tpc.10.6.905.
On the tropical legume Sesbania rostrata, stem-borne nodules develop after inoculation of adventitious root primordia with the microsymbiont Azorhizobium caulinodans. A cDNA clone, Srchi13, with homology to acidic class III chitinase genes, corresponds to an early nodulin gene with transiently induced expression during nodule ontogeny. Srchi13 transcripts accumulated strongly 2 days after inoculation, decreased from day 7 onward, and disappeared in mature nodules. Induction was dependent on Nod factor-producing bacteria. Srchi13 was expressed around infection pockets, in infection centra, around the developing nodule and its vascular bundles, and in uninfected cells of the central tissue. The specific and transient transcript accumulation together with the lipochitooligosaccharide degradation activity of the recombinant protein hint at a role of Srchi13 in normal nodule ontogeny by limiting the action of Nod factors.
在热带豆科植物喙荚田菁上，不定根原基接种共生微生物茎瘤固氮根瘤菌后会形成茎瘤。一个与酸性III类几丁质酶基因具有同源性的cDNA克隆Srchi13，对应于一个早期结瘤素基因，在根瘤发育过程中其表达受到瞬时诱导。接种后2天，Srchi13转录本大量积累，从第7天开始减少，并在成熟根瘤中消失。这种诱导依赖于产生结瘤因子的细菌。Srchi13在感染位点周围、感染中心、发育中的根瘤及其维管束周围以及中央组织的未感染细胞中表达。重组蛋白的脂壳寡糖降解活性以及其转录本的特异性和瞬时积累表明，Srchi13通过限制结瘤因子的作用在正常根瘤发育中发挥作用。
