The receptor-like kinase ERECTA contributes to the shade-avoidance syndrome in a background-dependent manner

LUCIANA KASULIN, YAMILIA AGROFOGLIO, JAVIER F BOTTO

ANNALS OF BOTANY

OXFORD UNIV PRESS

Lugar: Oxford; Año: 2013 p. 811 - 819

0305-7364

Background and Aims Plants growing at high densities perceive a decrease in the red to far-red (R/FR) ratioof incoming light. These changes in light quality trigger a suite of responses collectively known as the shadeavoidancesyndrome (SAS) including hypocotyl and stem elongation, inhibition of branching and accelerationof flowering.Methods Quantitative trait loci (QTLs) were mapped for hypocotyl length to end-of-day far-red (EOD), a simulatedshade-avoidance response, in recombinant inbred line (RIL) populations of Arabidopsis thaliana seedlings,derived from Landsberg erecta (Ler) and three accessions (Columbia, Col; Nossen, No-0; and Cape VerdeIslands, Cvi-0). Key Results Five loci were identified as being responsible for the EOD response, with a positive contribution ofLer alleles on the phenotype independently of the RIL population. Quantitative complementation analysis andtransgenic lines showed that PHYB is the candidate gene for EODRATIO5 in the Ler × Cvi-0 RIL population,but not for two co-localized QTLs, EODRATIO1 and EODRATIO2 mapped in the Ler × No-0 and Ler × ColRIL populations, respectively. The ERECTA gene was also implicated in the SAS in a background-dependentmanner. For hypocotyl length EOD response, a positive contribution of erecta alleles was found in Col andVan-0, but not in Ler, Cvi-0, Hir-1 or Ws. Furthermore, pleiotropic effects of ERECTA in the EOD responsewere also detected for petiole and lamina elongation, hyponastic growth, and flowering time.Conclusions The results show that the analysis of multiple mapping populations leads to a better understandingof the SAS genetic architecture. Moreover, the background- and trait-dependent contribution of ERECTA in theSAS suggest that its function in shaded natural environments may be relevant for some populations in differentphases of plant development. It is proposed that ERECTA is involved in canalization processes buffering thegenetic variation of the SAS against environmental light fluctuations.