BackgroundZinc finger homeodomain proteins (ZHD) constitute a plant-specific transcription factor family with a conserved DNA binding homeodomain and a zinc finger motif. Members of the ZHD protein family play important roles in plant growth, development, and stress responses. Genome-wide characterization of ZHD genes has been carried out in several model plants, including Arabidopsis thaliana and Oryza sativa, but not yet in tomato (Solanum lycopersicum).ResultsIn this study, we performed the first comprehensive genome-wide characterization and expression profiling of the ZHD gene family in tomato (Solanum lycopersicum). We identified 22 SlZHD genes and classified them into six subfamilies based on phylogeny. The SlZHD genes were generally conserved in each subfamily, with minor variations in gene structure and motif distribution. The 22 SlZHD genes were distributed on six of the 12 tomato chromosomes, with segmental duplication detected in four genes. Analysis of Ka/Ks ratios revealed that the duplicated genes are under negative or purifying selection. Comprehensive expression analysis revealed that the SlZHD genes are widely expressed in various tissues, with most genes preferentially expressed in flower buds compared to other tissues. Moreover, many of the genes are responsive to abiotic stress and phytohormone treatment.ConclusionSystematic analysis revealed structural diversity among tomato ZHD proteins, which indicates the possibility for diverse roles of SlZHD genes in different developmental stages as well as in response to abiotic stresses. Our expression analysis of SlZHD genes in various tissues/organs and under various abiotic stress and phytohormone treatments sheds light on their functional divergence. Our findings represent a valuable resource for further analysis to explore the biological functions of tomato ZHD genes.Electronic supplementary materialThe online version of this article (10.1186/s12864-017-4082-y) contains supplementary material, which is available to authorized users.

Growth regulating factors (GRFs) are plant-specific transcription factors that are involved in diverse biological and physiological processes, such as growth, development and stress and hormone responses. However, the roles of GRFs in vegetative and reproductive growth, development and stress responses in tomato (Solanum lycopersicum) have not been extensively explored. In this study, we characterized the 13 SlGRF genes. In silico analysis of protein motif organization, intron–exon distribution, and phylogenetic classification confirmed the presence of GRF proteins in tomato. The tissue-specific expression analysis revealed that most of the SlGRF genes were preferentially expressed in young and growing tissues such as flower buds and meristems, suggesting that SlGRFs are important during growth and development of these tissues. Some of the SlGRF genes were preferentially expressed in fruits at distinct developmental stages suggesting their involvement in fruit development and the ripening process. The strong and differential expression of different SlGRFs under NaCl, drought, heat, cold, abscisic acid (ABA), and jasmonic acid (JA) treatment, predict possible functions for these genes in stress responses in addition to their growth regulatory functions. Further, differential expression of SlGRF genes upon gibberellic acid (GA3) treatment indicates their probable function in flower development and stress responses through a gibberellic acid (GA)-mediated pathway. The results of this study provide a basis for further functional analysis and characterization of this important gene family in tomato.

The actin depolymerizing factor (ADF) proteins have growth, development, defense-related and growth regulatory functions in plants. The present study used genome-wide analysis to investigate ADF family genes in tomato. Eleven tomato ADF genes were identified and differential expression patterns were found in different organs. SlADF6 was preferentially expressed in roots, suggesting its function in root development. SlADF1, SlADF3 and SlADF10 were predominately expressed in the flowers compared to the other organs and specifically in the stamen compared to other flower parts, indicating their potential roles in pollen development. The comparatively higher expression of SlADF3 and SlADF11 at early fruit developmental stages might implicate them in determining final fruit size. SlADF5 and SlADF8 had relatively higher levels of expression five days after the breaker stage of fruit development, suggesting their possible role in fruit ripening. Notably, six genes were induced by cold and heat, seven by drought, five by NaCl, and four each by abscisic acid (ABA), jasmonic acid (JA) and wounding treatments. The differential expression patterns of the SlADF genes under different types of stresses suggested their function in stress tolerance in tomato plants. Our results will be helpful for the functional characterization of ADF genes during organ and fruit development of tomato under different stresses.

This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. ABSTRACT Rapeseed is a member of family Brassicaceae, cultivated as oil crop. Rapeseed oil is being utilized from early civilization, but its popularity being declined from the mid-nineteenth century due to presence of erucic acid (C22:1) and glucosinolates. Thereby, several attempts have been made to develop cultivars free from those toxins. In the past 20 years, breeders got success in developing '00'-quality rapeseed, known as 'Canola'. The target mutagenesis of fae-1 and fae-2 of Brassica napus ensured such success. Thereafter, 'canola' regains its market as a healthy vegetable oil. Moreover, high oleic acid rapeseed lines, with 86% oleic acid, have been developed by using chemical mutagenesis of FAD2 alleles responsible for desaturation of oleic acid (C18:1) to linoleic acid (C18:2). Recently, high erucic acid rapeseed oil regained interest for biodegradable plastic, cosmetic, emollient industries and for biodiesel. Therefore, breeding approaches have been pursued; unfortunately, that were failed to reach erucic acid level beyond 50% in seed-oil. Rapeseed genotypes over-expressed with Ld-LPAAT separately and Ld-LPAAT-FAE chimaric construct together were tried but failed to reach the erucic acid content more than 60%. Thereof, combined effort of conventional breeding and transgenic approaches are brought together to overcome three hypothesized bottlenecks; reviewed in this article, which restricted erucic acid level near to 60%. Finally, rapeseed genotypes with 78% erucic acid were developed successfully. This material is now available in Germany for using in emollient industries and for biodiesel. Therefore, this article is reviewed on the current status and future outlook for modification of fatty acid profiles of rapeseed oil for its end-use as food, industrial feed-stock and biodiesel.

No abstract