Isolation and characterization of high temperature-resistant germination mutants of Arabidopsis thaliana.
Temperature is a primary environmental cue for seed germination of many weeds and vegetables. To investigate the mechanism of germination regulation by temperature, we selected five high temperature (thermoinhibition)-resistant germination mutants (TRW lines) from 20,000 T-DNA insertion lines of Arabidopsis. Segregation analyses indicated that each of the five lines had single locus recessive mutations. The seeds of TRW134-15 and TRW187 showed reduced sensitivity to ABA and also to the gibberrellin biosynthesis inhibitor, paclobutrazol. Genetic and nucleotide sequencing analyses indicated that TRW187 is a new allele of abi3 (abi3-14). TRW71-1 exhibited a maternal effect for both thermoinhibition-resistant and transparent testa phenotypes, and genetic analysis revealed that the mutation was allelic to tt7 (tt7-4 sib). Interestingly, the seeds of reduced dormancy mutants rdo1, rdo2, rdo3 and rdo4 were also thermoinhibition tolerant, and all the TRW seeds showed reduced dormancy. Like rdo3, TRW13-1 had shorter siliques and slightly shorter stems than the wild type. The mutation of TRW13-1 was mapped to the bottom arm of chromosome 1 where rdo3 has also been mapped, but the two mutants are not allelic. We designated TRW13-1 as thermoinhibition-resistant germination 1 (trg1). We also mapped the ABA-insensitive mutation of TRW134-15 to the bottom arm of chromosome 5 and named it trg2. These results show that both embryo/endosperm and maternal factors contribute to germination inhibition at supraoptimal temperatures in Arabidopsis. In addition, we confirm the role of ABA in thermoinhibition of seed germination and a link between seed physiological dormancy and response to high temperature.
Tamura
Noriko
N
Laboratory of Plant Molecular Physiology, Department of Life Sciences, School of Agriculture, Meiji University, Kawasaki 214-8571, Japan.
Yoshida
Takahiro
T
Tanaka
Arata
A
Sasaki
Ryuta
R
Bando
Asuka
A
Toh
Shigeo
S
Lepiniec
Loïc
L
Kawakami
Naoto
N
D000040:Abscisic Acid / Q000502:physiology; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics; D001483:Base Sequence; D018525:Germination / Q000502:physiology*; D005875:Gibberellins / Q000502:physiology; D008969:Molecular Sequence Data; D009154:Mutation; D012639:Seeds / Q000502:physiology*; D013696:Temperature; D014157:Transcription Factors
C091601:ABI3 protein, Arabidopsis; D029681:Arabidopsis Proteins; D005875:Gibberellins; D014157:Transcription Factors; D000040:Abscisic Acid