Selecting the superior late-leafing genotypes of Persian walnut (Juglans regia L.) using morphological and pomological evaluations

Genome-Wide Identification of the CBF Gene Family and ICE Transcription Factors in Walnuts and Expression Profiles under Cold Conditions

Cold stress impacts woody tree growth and perennial production, especially when the temperature rapidly changes in late spring. To address this issue, we conducted the genome-wide identification of two important transcription factors (TFs), CBF (C-repeat binding factors) and ICE (inducers of CBF expression), in three walnut (Juglans) genomes. Although the CBF and ICE gene families have been identified in many crops, very little systematic analysis of these genes has been carried out in J. regia and J. sigillata. In this study, we identified a total of 16 CBF and 12 ICE genes in three Juglans genomes using bioinformatics analysis. Both CBF and ICE had conserved domains, motifs, and gene structures, which suggests that these two TFs were evolutionarily conserved. Most ICE genes are located at both ends of the chromosomes. The promoter cis-regulatory elements of CBF and ICE genes are largely involved in light and phytohormone responses. Based on 36 RNA sequencing of leaves from four walnut cultivars ('Zijing', 'Lvling', 'Hongren', and 'Liao1') under three temperature conditions (8 °C, 22 °C, and 5 °C) conditions in late spring, we found that the ICE genes were expressed more highly than CBFs. Both CBF and ICE proteins interacted with cold-related proteins, and many putative miRNAs had interactions with these two TFs. These results determined that CBF1 and ICE1 play important roles in the tolerance of walnut leaves to rapid temperature changes. Our results provide a useful resource on the function of the CBF and ICE genes related to cold tolerance in walnuts.

Morphological characterization and interspecific variation among five species of Ziziphus genus to select superiors in Iran

BACKGROUND

Several species of the genus Ziziphus are used worldwide for their medicinal and therapeutic properties. The present study aimed to investigate the phenotypic variation of five species of the Ziziphus genus, including Z. jujuba Mill. (25 accessions), Z. mauritiana Lam. (25 accessions), Z. spina-christi L. (25 accessions), Z. nummularia L. (10 accessions), and Z. xylopyrus Willd. (10 accessions) from Markazi, Sistan-va-Baluchestan, and Khuzestan provinces, Iran.

RESULTS

The investigated accessions have significant differences in terms of all the measured as revealed using analysis of variance (ANOVA, P < 0.01). The range of fruit weight was 0.43-1.29 g in Z. jujuba, 17.85-29.87 g in Z. mauritiana, 0.94-3.44 g in Z. spina-christi, 0.93-2.02 g in Z. nummularia, and 0.91-3.02 g in Z. xylopyrus. All the measured traits showed significant and positive correlations with each other. Multiple regression analysis (MRA) results showed that fruit length, stone width, stone weight, stone length, and fruit width have significant effects on fruit weight, and thus their fluctuations have a significant effect on increasing or decreasing fruit weight. The accessions were grouped into two main clusters using hierarchical cluster analysis. The first cluster (I) included all the accessions of Z. mauritiana, while the second cluster (II) contained the accessions of the rest species forming two sub-clusters.

CONCLUSION

Based on the commercial characters, accessions no. 12, 13, 17, 23, and 24 in Z. jujuba, accessions no. 3, 9, 17, 18, 20, 22, and 23 in Z. mauritiana, accessions no. 5, 6, 8, 13, 19, 22, and 24 in Z. spina-christi, accessions no. 3, 7, and 9 in Z. nummularia, and accessions no. 2, 4, 7, and 10 in Z. oxyphylla showed the highest fruit weight and thus can be suggested as superior for cultivation or use in breeding programs due to having larger fruits.