Alfalfa Enod12 genes are differentially regulated during nodule development by Nod factors and Rhizobium invasion.

AUTOR(ES)

Bauer, P

RESUMO

MsEnod12A and MsEnod12B are two early nodulin genes from alfalfa (Medicago sativa). Differential expression of these genes was demonstrated using a reverse transcription-polymerase chain reaction approach. MsEnod12A RNA was detected only in nodules and not in other plant tissues. In contrast, MsEnod12B transcripts were found in nodules and also at low levels in roots, flowers, stems, and leaves. MsEnod12B expression was enhanced in the root early after inoculation with the microsymbiont Rhizobium meliloti and after treatment with purified Nod factors, whereas MsEnod12A induction was detected only when developing nodules were visible. In situ hybridization showed that in nodules, MsEnod12 expression occurred in the infection zone. In empty Fix- nodules the MsEnod12A transcript level was much reduced, and in spontaneous nodules it was not detectable. These data indicate that MsEnod12B expression in roots is related to the action of Nod factors, whereas MsEnod12A expression is associated with the invasion process in nodules. Therefore, alfalfa possesses different mechanisms regulating MsEnod12A and MsEnod12B expression.

Documentos Relacionados

• The exoD gene of Rhizobium meliloti encodes a novel function needed for alfalfa nodule invasion.
• Rhizobium meliloti elicits transient expression of the early nodulin gene ENOD12 in the differentiating root epidermis of transgenic alfalfa.
• All nod genes of Rhizobium meliloti are involved in alfalfa nodulation by exo mutants.
• Two divergent catalase genes are differentially regulated during Aspergillus nidulans development and oxidative stress.
• Specific oligosaccharide form of the Rhizobium meliloti exopolysaccharide promotes nodule invasion in alfalfa.