Background: Physic nut (Jatropha curcas), an inedible oilseed plant, is among the most promising alternative energy sources because of its high oil content, rapid growth and extensive adaptability. Proteins encoded by MADS-box family genes are important transcription factors participated in regulating plant growth, seed development and responses to abiotic stress. However, there has been no in-depth research on the MADS-box genes and their roles in physic nut. Results: In our study, 63 MADS-box genes (JcMADSs) were identified in the physic nut genome, and classed into five groups (MIKC C , Mα, Mβ, Mγ, MIKC*) according to phylogenetic comparison with Arabidopsis homologs. Expression profile analysis based on RNA-seq suggested that many JcMADS genes had the strongest expression in seeds, and seven of them responded in leaves to at least one abiotic stressor (drought and/or salinity) at one or more time points. Transient expression analysis and a transactivation assay indicated that JcMADS40 is a nucleuslocalized transcriptional activator. Plants overexpressing JcMADS40 did not show altered plant growth, but the overexpressing plants did exhibit reductions in grain size, grain length, grain width, 1000-seed weight and yield per plant. Further data on the reduced grain size in JcMADS40-overexpressing plants supported the putative role of JcMADS genes in seed development. Conclusions: This study will be useful in order to further understand the process of MADS-box genes involved in regulating growth and development in addition to their functions in abiotic stress resistance, and will eventually provide a theoretical basis for the functional investigation and the exploitation of candidate genes for the molecular improvement of physic nut.

Plant-specific WOX transcription factors have important regulatory functions in plant development and response to abiotic stress. However, the identification and functional analysis of members of the WOX family have rarely been reported in the physic nut plant until now. Our research identified 12 WOX genes (JcWOXs) in physic nut, and these genes were divided into three groups corresponding to the ancient clade, WUS clade, and intermediate clade. Expression analysis based on RNA-seq and qRT-PCR showed that most of the JcWOX genes were expressed in at least one of the tissues tested, whereas five genes were identified as being highly responsive to drought and salt stresses. Subcellular localization analysis in Arabidopsis protoplast cells showed that JcWOX5 encoded a nuclear-localized protein. JcWOX5-overexpression plants increased sensitivity to drought stress, and transgenic plants suggested a lower proline content and CAT activity, higher relative electrolyte leakage, higher MDA content, and higher rate of water loss under drought conditions. Expression of some stressrelated genes was obviously lower in the transformed rice lines as compared to their expression in wild-type rice lines under drought stress. Further data on JcWOX5overexpressing plants reducing drought tolerance verified the potential role of JcWOX genes in responsive to abiotic stress. Collectively, the study provides a foundation for further functional analysis of JcWOX genes and the improvement of physic nut crops.

Background: Physic nut (Jatropha curcas), a non-edible oilseed plant, is among the most promising alternative energy sources because of its high seed oil content, rapid growth and extensive adaptability. Proteins encoded by MADS-box genes are important transcription factors involved in the regulation of plant growth, seed development and responses to abiotic stress. However, there has been no in-depth research on the MADS-box genes and their roles in physic nut. Results:In the present study, 63 MADS-box genes (JcMADSs) were identified in the physic nut genome, and classed into five groups (MIKC, Mα, Mβ, Mγ, Mδ) based on phylogenetic comparison with Arabidopsis homologs. Expression profile analysis based on RNA-seq suggested that many JcMADS genes were expressed most strongly in seeds, and seven of them responded in leaves to at least one abiotic stressor (drought and/or salinity) at one or more time points. Transient expression analysis and a transactivation assay indicated that JcMADS05 is a nucleus-localized transcriptional activator.Plants overexpressing JcMADS05 did not show altered plant growth, but the overexpressing plants did exhibit reductions in grain size, grain length, grain width, 1000-seed weight and yield per plant.Further data on the reduced grain size in JcMADS05-overexpressing plants supported the putative role of JcMADS genes in seed development. Conclusions:This study will be useful in understanding the involvement of MADS-box genes in growth and development in addition to their functions in abiotic stress resistance, and will ultimately form the basis for functional characterization and the exploitation of candidate genes for the genetic engineering of physic nut. BackgroundThe regulation of plant growth, development and stress responses is complex and is coordinated by many mechanisms. These mechanisms are under the control of a series of related genes acting through complex regulatory networks. In these processes, transcription factor (such as members of the MYB, HD-Zip, ARF, NAC, MADS-box, and ERF gene families) specifically recognize cis-regulatory elements present in the promoter regions of these genes, and regulate their expression so as to modulate a wide range of biochemical, physiological and developmental processes [1][2][3][4][5][6] (Ferrandiz All Arabidopsis MADS-box protein sequences were used as queries in a BlastP search to identify physic nut proteins. A Hidden Markov Model (HMM) search was also performed against the physic nut protein database using the MADS-domain PF03106. In total, 63 putative MADS proteins were identified in physic nut, with the presence of the MADS-box domain in each of them being confirmed by a SMART website search. These genes were named sequentially from JcMADS01 to JcMADS63 according to their chromosomal locations (Additional File 1). The 63 JcMADS genes ranged in length from 195 (JcMADS35) to 1164 (JcMADS34), thus potentially the proteins encoded would be from 64 to The research was conceived and designed by XB and YT. The experiments were performed ...

Background: Physic nut (Jatropha curcas), a non-edible oilseed plant, is among the most promising alternative energy sources because of its high seed oil content, rapid growth and extensive adaptability. Proteins encoded by MADS-box genes are important transcription factors involved in the regulation of plant growth, seed development and responses to abiotic stress. However, there has been no in-depth research on the MADS-box genes and their roles in physic nut. Results: In the present study, 63 MADS-box genes (JcMADSs) were identified in the physic nut genome, and classed into five groups (MIKC, Mα, Mβ, Mγ, MIKC*) based on phylogenetic comparison with Arabidopsis homologs. Expression profile analysis based on RNA-seq suggested that many JcMADS genes were expressed most strongly in seeds, and seven of them responded in leaves to at least one abiotic stressor (drought and/or salinity) at one or more time points. Transient expression analysis and a transactivation assay indicated that JcMADS40 is a nucleus-localized transcriptional activator. Plants overexpressing JcMADS40 did not show altered plant growth, but the overexpressing plants did exhibit reductions in grain size, grain length, grain width, 1000-seed weight and yield per plant. Further data on the reduced grain size in JcMADS40-overexpressing plants supported the putative role of JcMADS genes in seed development. Conclusions: This study will be useful in understanding the involvement of MADS-box genes in growth and development in addition to their functions in abiotic stress resistance, and will ultimately form the basis for functional characterization and the exploitation of candidate genes for the genetic engineering of physic nut.

Background: Physic nut (Jatropha curcas), a non-edible oilseed plant, is among the most promising alternative energy sources because of its high seed oil content, rapid growth and extensive adaptability. Proteins encoded by MADS-box genes are important transcription factors involved in the regulation of plant growth, seed development and responses to abiotic stress. However, there has been no in-depth research on the MADS-box genes and their roles in physic nut. Results: In the present study, 63 MADS-box genes (JcMADSs) were identified in the physic nut genome, and classed into five groups (MIKCC, Mα, Mβ, Mγ, MIKC*) based on phylogenetic comparison with Arabidopsis homologs. Expression profile analysis based on RNA-seq suggested that many JcMADS genes were expressed most strongly in seeds, and seven of them responded in leaves to at least one abiotic stressor (drought and/or salinity) at one or more time points. Transient expression analysis and a transactivation assay indicated that JcMADS40 is a nucleus-localized transcriptional activator. Plants overexpressing JcMADS40 did not show altered plant growth, but the overexpressing plants did exhibit reductions in grain size, grain length, grain width, 1000-seed weight and yield per plant. Further data on the reduced grain size in JcMADS40-overexpressing plants supported the putative role of JcMADS genes in seed development. Conclusions: This study will be useful in understanding the involvement of MADS-box genes in growth and development in addition to their functions in abiotic stress resistance, and will ultimately form the basis for functional characterization and the exploitation of candidate genes for the genetic engineering of physic nut.