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Flax is an important cash crop globally with a variety of commercial uses. It has been widely used for fiber, oil, nutrition, feed and in composite materials. Growth regulatory factor (GRF) is a transcription factor family unique to plants, and is involved in regulating many processes of growth and development. Bioinformatics analysis of the GRF family in flax predicted 17 LuGRF genes, which all contained the characteristic QLQ and WRC domains. Equally, 15 of 17 LuGRFs (88%) are predicted to be regulated by lus-miR396 miRNA. Phylogenetic analysis of GRFs from flax and several other well-characterized species defined five clades; LuGRF genes were found in four clades. Most LuGRF gene promoters contained cis-regulatory elements known to be responsive to hormones and stress. The chromosomal locations and collinearity of LuGRF genes were also analyzed. The three-dimensional structure of LuGRF proteins was predicted using homology modeling. The transcript expression data indicated that most LuGRF family members were highly expressed in flax fruit and embryos, whereas LuGRF3, LuGRF12 and LuGRF16 were enriched in response to salt stress. Real-time quantitative fluorescent PCR (qRT-PCR) showed that both LuGRF1 and LuGRF11 were up-regulated under ABA and MeJA stimuli, indicating that these genes were involved in defense. LuGRF1 was demonstrated to be localized to the nucleus as expected for a transcription factor. These results provide a basis for further exploration of the molecular mechanism of LuGRF gene function and obtaining improved flax breeding lines. [ABSTRACT FROM AUTHOR]

• The genetic diversity of celery germplasms was evaluated based on agronomic traits, quality traits and heat tolerance. • Apigenin and cellulose were the main contributors to the variation of quality traits. • The comprehensive evaluation value of celery after heat stress had a highly significant positive correlation with the heat damage index. • The heat resistance of celery was related to its hollow/solid and color. Existing celery germplasm resources must be evaluated prior to celery biological research and application of germplasm resources. In this study, 14 agronomic and quality traits, and heat-resistance of 50 celery cultivars were analyzed. The results showed that the coefficients of variation of the 14 traits ranged from 1.73% to 64.69%, 50 samples of celery could be divided into 5 groups by cluster analysis. The primary sources of variation in agronomic traits were petiole color, hollow/solid, and yield per plant, and the primary sources of variation of quality traits were apigenin and cellulose. The photosynthetic parameters and heat damage index was investigated, and the correlation between celery germplasm resources and heat-resistance was analyzed. The result showed that heat-resistance was correlated with its hollow/solid and color. This study analyzed the genetic diversity of celery germplasm resources, screened heat-resistant and heat-sensitive varieties, and performed an association analysis with the germplasm resources, which laid the foundation for the subsequent selection of heat-resistant celery varieties. [ABSTRACT FROM AUTHOR]