Natural variation in ecophysiological traits of waterlogging tolerance in Lotus japonicus

STRIKER GG; MANZUR ME; PLOSCHUK RA; CASAS C; CASAL JJ

Manila

Conferencia; The 11th International Conference on Plant Anaerobiosis; 2013

International Society for Plant Anaerobiosis

Lotus japonicus is a model legume closely related to waterlogging-tolerant forages L. tenuis and L. corniculatus, having a large number of genetic tools to improve our knowledge on legume?s waterlogging tolerance. We screened responses of 2 month-old plants of 94 recombinant inbred lines of L. japonicus (RILs derived from Gifu x Miyakojima MG-20) subjected to control and waterlogging conditions for 21 days (4 replicates per RIL/treatment). Assessed parameters were:  shoot, root and pods dry mass; number of main stems and total branches, total length of shoots; roots total length and absorption surface, and carbon fixation-related variables like stomatal conductance and chlorophyll fluorescence. We examined correlations and performed a multivariate method to comparatively group and weight the importance of phenotypical parameters under each treatment. Results showed that, under control condition, shoot mass was positively correlated to root mass (r=0.71), total plant length (r=0.68), number of branches (r=0.68), root system length and surface (r=0.53 and 0.57), and stomatal conductance (r=0.84). Root mass correlated to root length and absorption surface (r=0.73 and 0.79), total plant length (r=0.38), number of main stems (r=0.28) and total branches (r=0.48). Pods mass correlated to total number of branches (r=0.27). Under waterlogging conditions, shoot mass correlated to root mass (r=0.82), total plant length (r=0.77), number of branches and main stems (r=0.52 and 0.40), root system length and surface (r=0.52 and 0.57), and stomatal conductance (r=0.84). Root mass of waterlogged plants was more strongly correlated with total plant length (r=0.62), number of main stems (r=0.51) and total branches (r=0.51) than under control conditions. Pods mass under waterlogging did not correlate with shoot mass but positively correlated with total plant length (r=0.24) and negatively with main stems number (r=-0.21). Based on these results a phenomic network for waterlogging tolerance in L. japonicus will be presented and discussed.