Haploinsufficiency after successive loss of signaling reveals a role for ERECTA-family genes in Arabidopsis ovule development.
The Arabidopsis genome contains three ERECTA-family genes, ERECTA (ER), ERECTA-LIKE 1 (ERL1) and ERL2 that encode leucine-rich repeat receptor-like kinases. This gene family acts synergistically to coordinate cell proliferation and growth during above-ground organogenesis with the major player, ER, masking the loss-of-function phenotypes of the other two members. To uncover the specific developmental consequence and minimum threshold requirement for signaling, ER-family gene function was successively eliminated. We report here that ERL2 is haploinsufficient for maintaining female fertility in the absence of ER and ERL1. Ovules of the haploinsufficient er-105 erl1-2 erl2-1/+ mutant exhibit abnormal development with reduced cell proliferation in the integuments and gametophyte abortion. Our analysis indicates that progression of integument growth requires ER-family signaling in a dosage-dependent manner and that transcriptional compensation among ER-family members occurs to maintain the required signaling threshold. The specific misregulation of cyclin A genes in the er-105 erl1-2 erl2-1/+ mutant suggests that downstream targets of the ER-signaling pathway might include these core cell-cycle regulators. Finally, genetic interaction of the ER family and the WOX-family gene, PFS2, reveals their contribution to integument development through interrelated mechanisms.
Pillitteri
Lynn Jo
LJ
Department of Biology, University of Washington, Seattle, WA 98195, USA.
Bemis
Shannon M
SM
Shpak
Elena D
ED
Torii
Keiko U
KU
D017360:Arabidopsis / Q000196:embryology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000502:physiology*; D004303:Dosage Compensation, Genetic; D005298:Fertility; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D006238:Haploidy; D018398:Homeodomain Proteins / Q000235:genetics / Q000502:physiology; D019656:Loss of Heterozygosity; D005810:Multigene Family / Q000502:physiology; D009866:Oogenesis / Q000235:genetics*; D030821:Plants, Genetically Modified; D011494:Protein Kinases / Q000235:genetics / Q000502:physiology; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000502:physiology*; D011956:Receptors, Cell Surface / Q000235:genetics / Q000502:physiology*; D012639:Seeds; D015398:Signal Transduction / Q000235:genetics
D029681:Arabidopsis Proteins; D018398:Homeodomain Proteins; C499750:PRETTY FEW SEEDS2 protein, Arabidopsis; D011956:Receptors, Cell Surface; D011494:Protein Kinases; C457763:ER protein, Arabidopsis; C502168:ERL1 protein, Arabidopsis; C502169:ERL2 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases