Genome-Wide Identification and Characterization of SPX Domain-Containing Members and Their Responses to Phosphate Deficiency inBrassica napus.
The importance of SPX domain-encoding proteins to phosphate (Pi) homeostasis and signaling pathways has been well-documented in rice andArabidopsis. However, global information and responses of SPX members to P stress in allotetraploidBrassica napus, one of the world's major oil crops that is sensitive to P deficiency, remain undefined. We identified a total of 69 SPX domain-containing genes in theB. napusgenome. Based on the domain organizations, these genes were classified into four distinct subfamilies-SPX (11), SPX-EXS (43), SPX-MFS (8), and SPX-RING (7)-that represented clear orthologous relationships to their family members inArabidopsis. Acis-element analysis indicated that 2 ∼ 4 P1BS elements were enriched in the promoter of SPX subfamily genes exceptBnaSPX4s. RNA-Seq analysis showed thatBnaSPXgenes were differentially expressed in response to Pi deficiency. Furthermore, quantitative real-time reverse transcription PCR revealed that nine SPX subfamily genes were significantly induced by Pi starvation and recovered rapidly after Pi refeeding. A functional analysis of two paralogousBnaSPX1genes in transgenicArabidopsisindicated their functional divergence during long-term evolution. This comprehensive study on the abundance, molecular characterization and responses to Pi deficiency ofBnaSPXgenes provides insights into the structural and functional diversities of these family members inB. napusand provides a solid foundation for future functional studies ofBnaSPXgenes.Highlight:The genome-wide identification and characterization of SPX genes inB. napusand their responses to Pi deficiency provide comprehensive insights into the structural and functional diversities of the family members inB. napusand their potential in Pi homeostasis and signaling responsiveness to Pi stress.
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural UniversityWuhan, China; Key Laboratory of Arable Land Conservation, Ministry of Agriculture, Huazhong Agricultural UniversityWuhan, China.
Hongyuan
H
Du
Key Laboratory of Arable Land Conservation, Ministry of Agriculture, Huazhong Agricultural University Wuhan, China.
Chang
C
Yang
Key Laboratory of Arable Land Conservation, Ministry of Agriculture, Huazhong Agricultural University Wuhan, China.
Guangda
G
Ding
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural UniversityWuhan, China; Key Laboratory of Arable Land Conservation, Ministry of Agriculture, Huazhong Agricultural UniversityWuhan, China.
Lei
L
Shi
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural UniversityWuhan, China; Key Laboratory of Arable Land Conservation, Ministry of Agriculture, Huazhong Agricultural UniversityWuhan, China.
Fangsen
F
Xu
Brassica napus; Pi stress; SPX domain gene; cis-element; expression profile; gene function; genome-wide analysis