Genome-Wide Identification, Expression Profile of the TIFY Gene Family in Brassica oleracea var. capitata, and Their Divergent Response to Various Pathogen Infections and Phytohormone Treatments

Abstract

TIFY, a plant-specific gene family with the conserved motif TIF[F/Y]XG, plays important roles in various plant biological processes. Here, a total of 36 TIFY genes were identified in the Brassica oleracea genome and classified into JAZ (22 genes), TIFY (7 genes), ZML (5 genes), and PPD (2 genes) subfamilies based on their conserved motifs, which were distributed unevenly across nine chromosomes with different lengths (339–1077 bp) and exon numbers (1–8). Following phylogenetic analysis with A. thaliana and B. rapa TIFY proteins, ten clades were obtained. The expression of these TIFY genes was organ-specific, with thirteen JAZ genes and two PPD genes showing the highest expression in roots and leaves, respectively. More importantly, the JAZs showed divergent responses to various pathogen infections and different phytohormone treatments. Compared with the susceptible line, most JAZs were activated after Plasmodiophora brassicae infection, while there were both induced and inhibited JAZs after Fusarium oxysporum or Xanthomonas campestris infection in the resistance line, indicating their probably distinct roles in disease resistance or susceptibility. Further, the JAZs were all upregulated after MeJA treatment, but were mostly downregulated after SA/ET treatment. In summary, these results contribute to our understanding of the TIFY gene family, revealing that JAZs may play crucial and divergent roles in phytohormone crosstalk and plant defense.

Genome-wide identification and functional analysis of the TIFY gene family in the response to multiple stresses in Brassica napus L.

“…TIFY proteins have proven to be important regulators in abiotic and biotic stress responses in plants. Since the Arabidopsis JAZ subfamily was identified as the vital repressor in JA signaling, increasing numbers of other JAZ proteins have been characterized as important stress-response regulators in various plant species, including B. rapa, B. oleracea, rice, cotton, tomato, poplar, grape, soybean, wheat, maize, rubber tree, Moso bamboo and purple false brome [36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][55][56][57]. However, no B. napus TIFY was isolated and identified over the whole genome.…”

“…Previous studies indicated that a total of 36 and 36 TIFY proteins were identified in B. rapa accession Chiifu-401-42 [ 51 ] and B. oleracea var. capitate lines (02–12 and D134) [ 41 ].…”

“…The results of a compared analysis between 36 BoTIFY genes in 02–12/D134 and 39 BoTIFY genes in TO1000 showed that the three new genes identified were Bo1g119100 ( BoJAZ3/4–2 ) , Bo7g082470 ( BoTIFY8–3 ) and Bo9g152530 ( BoTIFY8–5 ) in TO1000. Further analysis showed that the study by Liu [ 51 ] had failed to identify BoJAZ gene Bol030895 (C01:31,896,448..31,899,117) in 02–12 (the homologous gene locus in TO1000 was Bo1g119100 ). Four members from the JAZ subfamily from B. napus contained only the Jas domain, and one member contained only the NT domain (Additional file 1 ).…”

“…For example, with the exception of Bra030986 , which has no orthologous TIFY genes in the B. napus An-subgenome, the distribution of all 34 TIFY genes in B. rapa were similar to those of the orthologous TIFY genes in B. napus An-subgenome (Additional file 3 ) [ 41 ]. Similar to the B. rapa vs B. napus An-subgenome, the distribution of TIFY genes in B. oleracea was similar to those of the orthologous TIFY genes in the B. napus Cn-subgenome (Additional file 3 ) [ 51 ].…”

“…Since B. napus is sensitive to environmental stress during all stages of growth and development, the production and quality of B. napus worldwide is deleteriously restricted by abiotic stresses and infection with S. sclerotiorum. Despite extensive studies of the TIFY family in many other species, including B. rapa and B. oleracea [36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51], TIFY has not yet been characterized in B. napus.…”