Study : RNA-seq of mycorrhizal Medicago truncatula roots under K+ deprivation
RNA-seq of mycorrhizal Medicago truncatula roots under K+ deprivation
Arbuscular mycorrhizal (AM) associations enhance the phosphorous and nitrogen nutrition of host plants, but little is known about their role in potassium (K+) nutrition. Medicago truncatula plants were co-cultured with the AM fungus Rhizophagus irregularis under high and low K+ regimes for six weeks. We determined how K+ deprivation affects plant development, mineral acquisition, and how these negative effects are tempered by the AM colonization. The transcriptional response of AM roots under K+ deficiency was analyzed by whole genome RNA-seq. K+ deprivation decreased root biomass, external K+ uptake, and modulated oxidative stress gene expression in M. truncatula roots. AM colonization induced specific transcriptional responses to K+ deprivation that seem to temper these negative effects. A gene network analysis revealed putative key regulators of these responses. This study confirmed that AM associations provide some tolerance to K+ deprivation to host plants, revealed that AM symbiosis modulates the expression of specific root genes to cope with this nutrient stress, and identified putative regulators participating in these tolerance mechanisms. Overall design: Medicago truncatula were inoculated or not with the arbuscular mycorrhizal fungus Rhizophagus irregularis and watered with a high (3.75 mM) or low (0.05 mM) potassium solution for six weeks. RNAs from three to four biological replicates composed of four plants each were sequenced.