TY - JOUR
T1 - Overlap of proteome changes in Medicago truncatula in response to auxin and Sinorhizobium meliloti
AU - Van Noorden, Giel E.
AU - Kerim, Tursun
AU - Goffard, Nicolas
AU - Wiblin, Robert
AU - Pellerone, Flavia I.
AU - Rolfe, Barry G.
AU - Mathesius, Ulrike
PY - 2007/6
Y1 - 2007/6
N2 - We used proteome analysis to identify proteins induced during nodule initiation and in response to auxin in Medicago truncatula. From previous experiments, which found a positive correlation between auxin levels and nodule numbers in the M. truncatula supernodulation mutant sunn (supernumerary nodules), we hypothesized (1) that auxin mediates protein changes during nodulation and (2) that auxin responses might differ between the wild type and the supernodulating sunn mutant during nodule initiation. Increased expression of the auxin response gene GH3:β-glucuronidase was found during nodule initiation in M. truncatula, similar to treatment of roots with auxin. We then used difference gel electrophoresis and tandem mass spectrometry to compare proteomes of wild-type and sunnmutant roots after 24 h of treatment with Sinorhizobium meliloti, auxin, or a control.We identified 131 of 270 proteins responding to treatment with S. meliloti and/or auxin, and 39 of 89 proteins differentially displayed between the wild type and sunn. The majority of proteins changed similarly in response to auxin and S. meliloti after 24 h in both genotypes, supporting hypothesis 1. Proteins differentially accumulated between untreated wild-type and sunn roots also showed changes in auxin response, consistent with altered auxin levels in sunn. However, differences between the genotypes after S. meliloti inoculation were largely not due to differential auxin responses. The role of the identified candidate proteins in nodule initiation and the requirement for their induction by auxin could be tested in future functional studies.
AB - We used proteome analysis to identify proteins induced during nodule initiation and in response to auxin in Medicago truncatula. From previous experiments, which found a positive correlation between auxin levels and nodule numbers in the M. truncatula supernodulation mutant sunn (supernumerary nodules), we hypothesized (1) that auxin mediates protein changes during nodulation and (2) that auxin responses might differ between the wild type and the supernodulating sunn mutant during nodule initiation. Increased expression of the auxin response gene GH3:β-glucuronidase was found during nodule initiation in M. truncatula, similar to treatment of roots with auxin. We then used difference gel electrophoresis and tandem mass spectrometry to compare proteomes of wild-type and sunnmutant roots after 24 h of treatment with Sinorhizobium meliloti, auxin, or a control.We identified 131 of 270 proteins responding to treatment with S. meliloti and/or auxin, and 39 of 89 proteins differentially displayed between the wild type and sunn. The majority of proteins changed similarly in response to auxin and S. meliloti after 24 h in both genotypes, supporting hypothesis 1. Proteins differentially accumulated between untreated wild-type and sunn roots also showed changes in auxin response, consistent with altered auxin levels in sunn. However, differences between the genotypes after S. meliloti inoculation were largely not due to differential auxin responses. The role of the identified candidate proteins in nodule initiation and the requirement for their induction by auxin could be tested in future functional studies.
UR - http://www.scopus.com/inward/record.url?scp=34250636716&partnerID=8YFLogxK
U2 - 10.1104/pp.107.099978
DO - 10.1104/pp.107.099978
M3 - Article
SN - 0032-0889
VL - 144
SP - 1115
EP - 1131
JO - Plant Physiology
JF - Plant Physiology
IS - 2
ER -