Peer Review #3 of "Genome-wide identification and expression analysis of fibrillin (FBN) gene family in tomato (Solanum lycopersicum L.) (v0.1)"

Background.Fibrillin (FBN) proteins are widely distributed in the photosynthetic organs.The members of FBN gene family play important roles in plant growth and development and response to hormone and stresses.Tomato is a vegetable crop with significantly economic value and model plant commonly used in research; however, the FBN family has not been systematical studied in tomato.Methods.In this study, 14 FBN genes were identified in tomato genome by Pfam and Hmmer 3.0 software.ExPASy, MEGA 6.0, MEME, GSDS, TBtools, PlantCARE and so on were used for physical and chemical properties analysis, phylogenetic analysis, gene structure and conserved motifs analysis, collinearity analysis and cis-acting element analysis of FBN family genes in tomato.Expression characteristics of SlFBNs in different tissues, fruit shape near isogenic lines (NILs), Pst DC3000 and ABA treatments were analyzed based on transcriptome data and quantitative Real-time qPCR (qRT-PCR) analysis.Results.The SlFBN family were divided into 11 subgroups.There were 8 FBN homologous gene pairs between tomato and Arabidopsis.All the members of SlFBN family contain PAP conserved domain, but their gene structure and conserved motifs showed apparent differences.The cis-acting elements of light and hormone (especially ethylene, methyl jasmonate (MeJA) and abscisic acid (ABA)) were widely distributed in the SlFBN promoter regions.The expression analysis found that most of SlFBNs were predominantly expressed in leaves of Heinz and S. pimpinellifolium LA1589, and showed higher expression in mature or senescent leaves than in young leaves.Expression analysis of different tissues and fruit shape NILs indicated SlFBN1, SlFBN2b and SlFBN7a might play important roles during tomato fruit differentiation.All of SlFBNs were responded to Pst DC3000 and ABA treatments.The results of this study contribute to exploring the functions and molecular mechanisms of SlFBNs in leaf development, fruit differentiation, stress and hormone responses.