Identification and Expression Analysis of Wheat TaGF14 Genes

Jun Guo, Shuang Dai, Haosheng Li, Aifeng Liu, Cheng Liu, Dungong Cheng, Xinyou Cao, Xiusheng Chu, Shengnan Zhai, Jianjun Liu, Zhendong Zhao, Jianmin Song

The 14-3-3 gene family members play key roles in various cellular processes. However, little is known about the numbers and roles of 14-3-3 genes in wheat. The aims of this study were to identifyTaGF14numbers in wheat by searching its whole genome through blast, to study the phylogenetic relationships with other plant species and to discuss the functions ofTaGF14s. The results showed that common wheat harbored 20TaGF14genes, located on wheat chromosome groups 2, 3, 4, and 7. Out of them, eighteenTaGF14sare non-ε proteins, and two wheatTaGF14genes,TaGF14iandTaGF14f, are ε proteins. Phylogenetic analysis indicated that these genes were divided into six clusters: cluster 1 (TaGF14d, TaGF14g, TaGF14j, TaGF14h, TaGF14c, andTaGF14n); cluster 2 (TaGF14k); cluster 3 (TaGF14b, TaGF14l, TaGF14m, andTaGF14s); cluster 4 (TaGF14a, TaGF14e, andTaGF14r); cluster 5 (TaGF14iandTaGF14f); and cluster 6 (TaGF14o, TaGF14p, TaGF14q, andTaGF14t). Tissue-specific gene expressions suggested that allTaGF14swere likely constitutively expressed, except two genes, i.e.,TaGF14pandTaGF14f. And the highest amount ofTaGF14transcripts were observed in developing grains at 20 days post anthesis (DPA), especially forTaGF14jandTaGF14l.After drought stress, five genes, i.e.,TaGF14c,TaGF14d,TaGF14g,TaGF14h, andTaGF14j, were up-regulated expression under drought stress for both 1 and 6 h, suggesting these genes played vital role in combating against drought stress. However, all theTaGF14swere down-regulated expression under heat stress for both 1 and 6 h, indicatingTaGF14smay be negatively associated with heat stress by reducing the expression to combat heat stress or through other pathways. These results suggested that cluster 1, e.g.,TaGF14j, may participate in the whole wheat developing stages, e.g., grain-filling (starch biosynthesis) and may also participate in combating against drought stress. Subsequently, a homolog ofTaGF14j,TaGF14-JM22, were cloned by RACE and used to validate its function. Immunoblotting results showed thatTaGF14-JM22protein, closely related toTaGF14d,TaGF14g, andTaGF14j, can interact with AGP-L, SSI, SSII, SBEIIa, and SBEIIb in developing grains, suggesting thatTaGF14slocated on group 4 may be involved in starch biosynthesis. Therefore, it is possible to develop starch-rich wheat cultivars by modifyingTaGF14s.