Nodulin 22 from Phaseolus vulgaris protects Escherichia coli cells from oxidative stress.
Plant genes that are induced during the formation and function of a root nodule are called nodulin genes. Cloning and functional analysis of nodule-specific gene products are of valuable help in establishing the role and requirements of the host plant for the specificity and effectiveness of the symbiosis. A cDNA clone (nod22) was isolated from Phaseolus vulgaris L. (common bean) cDNA library derived from Rhizobium-infected roots. Nodulin 22 (Nod22) transcripts are accumulated from early to late stages in root nodule development. RT-PCR in situ studies indicated that Nod22 transcripts are highly accumulated in cortical, vascular bundle and infected cells. The deduced Nod22 protein contains a highly hydrophobic N-terminus, with signal peptide characteristics, and a C-terminal extension with high identity to the alpha-crystallin domains found in alpha-crystallin lens chaperone, and other small heat-shock proteins. These domains have not been previously described in other known nodulins, but have been observed in small heat-shock proteins found in plant tissues exposed to elevated temperature and oxidative stress. Nod22, when it is over-expressed in Escherichia coli, cells confers protection against oxidative stress suggesting its possible role in plant host protection from oxidative toxicity during the Rhizobium-legume symbiosis.
Mohammad
Asif
A
Departamento de Biología Molecular de Plantas, Universidad Nacional Autónoma de México, Apartado Postal 510-3, 62271 Cuernavaca, Morelos, México.
Miranda-Ríos
Juan
J
Navarrete
Georgina Estrada
GE
Quinto
Carmen
C
Olivares
Juan Elías
JE
García-Ponce
Berenice
B
Sánchez
Federico
F
D000595:Amino Acid Sequence; D001483:Base Sequence; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D030781:Organisms, Genetically Modified; D018384:Oxidative Stress / Q000502:physiology*; D027805:Phaseolus / Q000235:genetics / Q000502:physiology*; D010940:Plant Proteins / Q000737:chemistry / Q000502:physiology*; D018517:Plant Roots / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D010940:Plant Proteins; D012333:RNA, Messenger