Repression of ABA-responsive alternative splicing by an Arabidopsis SR protein relieves ABA inhibition of early plant growth
Laloum, Tom (Gulbenkian Institute for Molecular Medicine)
Martín, Giomar (Centre de Rercerca en Agrogenòmica)
Lewinski, Martin (Bielefeld University)
Yanez, Romana J. R. (Gulbenkian Institute for Molecular Medicine)
Köster, Tino (Bielefeld University)
Paixão, Tiago (Gulbenkian Institute for Molecular Medicine)
Staiger, Dorothee (Bielefeld University)
Duque, Paula (Gulbenkian Institute for Molecular Medicine)

Fecha:	2026
Resumen:	The phytohormone abscisic acid (ABA) inhibits postgermination growth under unfavorable conditions to delay the seedling's transition to the autotrophic stage and promote plant survival. Stress-induced ABA accumulation is well established to trigger extensive transcriptional changes, but it is becoming clear that ABA also relies on alternative splicing to enhance stress tolerance. However, the molecular components modulating the posttranscriptional regulation of ABA control of early plant growth remain largely unknown. Here, we show that Arabidopsis thaliana SR34a, a member of the highly conserved serine/arginine-rich (SR) protein family of RNA-binding proteins, reduces sensitivity to ABA, promoting seedling establishment under stress. We found that ABA concentrations that allow greening of wild-type seedlings arrest the growth of a loss-of-function mutant for SR34a upon seed germination. Accordingly, the mutant displays hypersensitivity to drought and salt stress during postgermination growth. Using individual-nucleotide resolution crosslinking and immunoprecipitation (iCLIP) combined with transcriptome analysis of the mutant, we reveal that SR34a regulates alternative splicing and binds predominantly to GCU-rich exonic sequences near splice sites. SR34a targets all types of alternative splicing events, including in RNAs encoding key ABA pathway regulators, to inhibit ABA-responsive splicing in germinated seeds. Our study establishes SR34a as a splicing regulator, shedding mechanistic light on how SR proteins regulate alternative splicing and counteract ABA inhibition of early plant growth.
Ayudas:	European Commission 706274 European Commission 101060102 Agencia Estatal de Investigación CNS2024-154790 Agencia Estatal de Investigación PID2021-125223NA-I00 Agencia Estatal de Investigación RYC2020-030160-I
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Lengua:	Anglès
Documento:	Article ; recerca ; Versió acceptada per publicar
Publicado en:	The Plant cell, Vol. 38, Num. 6 (June 2026) , art. koag127, ISSN 1532-298X

DOI: 10.1093/plcell/koag127

Disponible a partir de: 2027-06-30 Postprint 71 p, 6.1 MB

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Documentos de investigación > Documentos de los grupos de investigación de la UAB > Centros y grupos de investigación (producción científica) > Ciencias > CRAG (Centro de Investigación en Agrigenómica)
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