Genome-Wide Identification Of The Early ABA Core Signalling Components In Brassica Oleracea

Abscisic acid is an important plant hormone,which plays a pivotal role at all stages of plant growth and development,including seed maturation and germination.ABA has been found to be involved in many plant physiological processes,especially in response to biotic and abiotic stress.ABA has a key role in preventing plants from adverse conditions.At present,the molecular basis of ABA signaling in Arabidopsis has been well elucidated.The core components of early ABA signal transduction pathway include ABA receptor PYR/PYLs(PYRABACTIN RESISTANCE/PYR1-like protein),PP2C(Protein phosphatase 2C),and Sn RK2(Sucrose non-fermenting 1-related protein kinase subfamily 2).These core components play extremely key roles in the modulation of ABA signal transduction pathway.In the current study,genome-wide annotations and functional analysis of PYR/PYL,PP2 C A,Sn RK2 s homologous genes in Brassica oleracea were performed.We obtained the following results:(1)A total of 24 PYR/PYL-like genes、14 PP2 C A-like genes and 13 SnRK2s-like genes were encoded by the genome of Brassica oleracea.Phylogenetic analysis revealed that PYR/PYL,PP2 C A,Sn RK2 s proteins are highly conserved between Brassica oleracea and Arabidopsis thalina.(2)Chromosome distribution revealed that the distribution density is different in each chromosome and only Bo PYR1 a and Bo PYL6 a cannot locate in any chromosome.(3)qRT-PCR result based heatmap showed that ABA induce the expression of many Bo PYR/PYL、Bo PP2 C A、Bo Sn RK2 s genes,such as Bo PYL9a、Bo PYL9b、Bo HAI2b、Bo HAI2a、Bo ABI1c、Bo Sn RK2.9、Bo Sn RK2.10、Bo Sn RK2.4a and so on.While,ABA also repress the expression of many Bo PYR/PYL genes,such as Bo PYR1a、Bo PYR1b、Bo PYR1 c.(4)ABA signal transduction was preliminarily reconstituted in Brassica oleracea.(5)Drought-tolerant material of Brassica napus were obtained through knock-out the negative regulator genes(PP2Cs)of ABA signaling were via CRISPR-Cas9 technology.In summary,the early ABA signalling pathway may be highly conserved in Brassica napus.Stress-tolerant orienting crop could be obtained via knock-out the negative regulator genes of stress response through CRISPR-Cas9 gene editing technology.