Abstract
Two distinct nonsymbiotic globin genes (LjNSG1, LjNSG2) were identified from genomic library of Lotus japonicus. Expression profiles using RT-PCR showed that LjNSG1 and LjNSG2 were expressed in all tissues of mature plants and enhanced expression was observed in mature nodules. The induction of both genes under various stress conditions and exogenous plant hormones were also investigated. LjNSG1 was induced not only under hypoxic and cold stress but also induced by the treatment with cytokinin and ABA. Mean while, LjNSG2 was induced only when the application of sucrose. Furthermore, both genes were induced in response to the inoculation of Mesorhizobium loti. The expression of LjNSG1 was also confirmed when the seedlings were treated with NO donor (SNAP). From these results, we considered the nonsymbiotic globin genes of L. japonicus might have cooperative function in NO-mediated stress response and establishment of symbiotic relation.
