Skip to content
Login Register

#TGMS

2 public questions tagged with this topic.

Plant Breeding 2

TGMS expression depends on:

Thermo-sensitive genetic male sterility expression modulated primarily by ambient temperature experienced by developing anthers during critical window from secondary branch differentiation to meiosis. Molecular switch involves temperature-dependent processing of UbL40 mRNA or activity of RNase Z encoded by tms5 gene. At high temperature exceeding critical sterility inducing point typically 26 to 28 Celsius for rice, abnormal accumulation of mRNA triggers ribonuclease dysfunction, persistence of tapetum and premature microspore degeneration resulting in complete pollen sterility with shriveled anthers. At lower temperature below threshold normal cleavage resumes, tapetum secretes nutrients, microspores fill starch and remain viable allowing self-seed harvest for line maintenance. Breeders exploit this thermosensory behavior to schedule sowings: winter low temperature nursery for multiplication, summer high temperature seed production for hybrid. This understanding supports competitive exam preparation for NEET, GATE and CSIR NET concepts linking genotype with phenotype through molecular pathways involving transcription factors, hormones and metabolic enzymes that regulate development, adaptation and reproductive biology in applied breeding programs.

Ref: Zhang et al PNAS 2012 tms5 RNase; Lee DS Rice TGMS molecular mechanism; Frontiers thermo-sensitive GMS review.

View Details
Plant Breeding 2

Environment-sensitive GMS includes:

Environment-sensitive genic male sterility category includes conditional nuclear sterility reversible by external cues, divided into thermo-sensitive GMS TGMS where sterile to fertile transition governed by temperature threshold during young panicle stage, and photoperiod-sensitive PGMS governed by day length threshold perceived via phytochrome signaling. Some lines respond to both termed PTGMS. Examples: rice TGMS line Annong S-1 becomes sterile above 24C, fertile below, while NK58S PGMS sterile under long days greater than 13.5 h fertile under short days. Genes identified include pms3 encoding long noncoding RNA whose promoter methylation photoperiod regulated, and tms5 encoding RNase Z. Conditional system enables two-line hybrid breeding: line multiplied as fertile under permissive environment and used as sterile parent under restrictive environment, reducing need for maintainer B-line simplifying breeding. This understanding supports competitive exam preparation for NEET, GATE and CSIR NET concepts linking genotype with phenotype through molecular pathways involving transcription factors, hormones and metabolic enzymes that regulate development, adaptation and reproductive biology in applied breeding programs.

Ref: Yuan Longping Two-line hybrid rice concept; Frontiers Plant Sci EGMS overview 2023; PubMed molecular TGMS PGMS.

View Details