25. Which plant hormones signal transduction pathway includes genes ‘rht, ‘spy’, ‘gai’?
(1) Auxin (2) Gibberlicacid
(3) Abscisic acid (4) Ethylene
Correct answer: (2) Gibberellic acid
Explanation:
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The genes rht, spy, and gai are well-characterized components of the gibberellic acid (GA) signaling pathway in plants.
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rht genes encode dwarfing alleles in wheat affecting GA response, crucial in the Green Revolution for semi-dwarf varieties.
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gai (GA insensitive) is a negative regulator (DELLA protein family) of GA signaling, which represses growth until GA presence relieves repression.
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spy (SPINDLY) is another negative regulator interacting within the GA pathway, modulating response sensitivity.
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These genes are not associated with auxin, abscisic acid, or ethylene pathways.
Option explanations:
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(1) Auxin – unrelated to rht, spy, gai genes.
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(2) Gibberellic acid – correct; these genes define the GA signaling pathway controlling plant growth and development.
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(3) Abscisic acid – involved in stress and dormancy pathways, not these genes.
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(4) Ethylene – controls senescence and fruit ripening, not linked with these genes.
5 Comments
Sonal Nagar
November 28, 2025Gibberellic acid
Manisha choudhary
November 29, 2025Gibberellic acid signalling m spy gene hoti h ( spindillyl) jo RGA ( repressor of Gibberellic acid) GAI ( gibberellic acid insensitive) ko active krti h gene ko off rkhti h
Jab GA hormone aata h too GID +GA Inka ubiquitination krwa deta h
Rht gene wheat m dwarfing allele ko encode krti h
Jo semidwarf varities m green revolution m crucial h
Manisha choudhary
November 29, 2025Gibberellic acid aata h tb sleepy and sneezy gene on hoti h jo GAI amd RGA kaa ubiquitination krwati h
GA alpha amylase,myB , XET gene kaa transcription krwata h
Sakshi Kanwar
December 1, 2025Gibberellic acid as rht encode dwarfism in wheat
And spy attach NAG to DELLA cause repression
Ankita Pareek
June 4, 2026In GA signalling when GA is present it bind with its receptor gid and and degrade gai which is a repressor
And spy gene is involved in modification
or attach NAG to.the della and increase its affinity causes more repression
Rht genes encode dwarfing genes in wheat
So that rht ,spy and gai are the components of gibberellic acid signalling