| Paulownia is a deciduous trees of Paulowniaceae,which is native to China.Paulownias have fast growing,good quality and strong adaptability,which made them often used as an important tree species to beautify the environment,with huge economic and ecological benefits.Paulownia will suffer from various stresses in the process of growth,which seriously affect the production and development of paulownia.Somatic embryogenesis receptor-like kinases(SERKs)are a class of protein kinases that exist widely in plants,which are related to plant growth and development and response to multiple stresses of adversity.In this study,the PfSERK gene family of Paulownia fortunei was screened from the whole genome,and the basic physicochemical properties and expression in different parts of the gene family were analyzed.The SERK gene in response to phytoplasma,drought and salt stress was screened by expression trend analysis,and the results were verified by quantitative real-time PCR(q RT-PCR).The main results of this study are summarized as follows:1.Twelve SERK genes of P.fortunei were identified.According to the phylogenetic tree,the SERK gene family can be divided into three subfamilies: Ⅰ,Ⅱand Ⅲ,including 4,5 and 3 members,respectively.The PfSERK protein domain of P.fortunei was highly conserved.Gene structure analysis showed that PfSERK gene contained 11 exons(except PfSERK12 containing 12 exons).The exons of the PfSERKs that shares a close evolutionary relationship were similar in length and position.All members of the PfSERK family contain light response elements,and most of them also have hormone and stress-related response elements,indicating that PfSERK genes are not only regulated by light,but also have hormone and stress-related regulatory mechanisms.The results of protein interaction network analysis showed that PfSERK protein could interact with many proteins,and the interaction proteins of PfSERK in the same subgroup were basically the same,and these interaction proteins were involved in the regulation of plant height,such as BAK1,BRI1 and SAC52.2.Gene fragment replication events are the main way for members of the PfSERK family to expand.Chromosome mapping showed that all PfSERK genes could be located on chromosomes and they were unevenly distributed on 8chromosomes of P.fortunei.Gene collinearity showed that 10 PfSERK genes formed10 homologous gene pairs.Different natural selections have taken place in the SERK family genes of P.fortunei under the adaptation of plant environment.The results of Ka/Ks analysis showed that the Ka/Ks ratios of 10 PfSERK collinear gene pairs were all less than 1,indicating that they were strictly purified and selected.3.The PfSERK gene responding to stress was screened.The tissue expression patterns of 12 PfSERK genes were analyzed by q RT-PCR.They were expressed in 5different parts of P.fortunei,and most of the PfSERK genes were highly expressed in the terminal bud.Expression trend analysis showed that two PfSERK genes responded to phytoplasma stress,in which PfSERK11 was targeted by sly-MIR171b-p5 and ssl-MIR171a-p5 to participate in the occurrence of Paulownia witches’ broom disease;in addition,seven PfSERK genes were screened to respond to drought and salt stress.In summary,this study used the genomic data of P.fortunei,combined with its expression pattern analysis to screen the PfSERK genes in response to phytoplasma,drought and salt stresses,which providing a theoretical basis for studying the functions of SERK family genes in the growth and development of P.fortunei,and also laying the foundation for the mining and utilization of functional genes of P.fortunei. |
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