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• Two MiCAL genes MiCAL1 and MiCAL2 were cloned from mango. • Overexpression of two MiCALs in Arabidopsis resulted in early flowering. • Overexpression of MiCAL1 led to terminal inflorescence, while MiCAL2 led to abnormal floral organ. • MiCAL1 and MiCAL2 can interacted with SEP1, SVP1, SVP2, SOC1G and Di19-4 protein. APETALA1 (AP1), CAULIFLOWER (CAL) and FRUITFULL (FUL) were homologous genes with redundant functions in the process of flower transformation and floral development in Arabidopsis. Two CALs genes, MiCAL1 and MiCAL2 , were cloned from mango (Mangifera indica L.). Their full-length sequences contained 717 bp and 714 bp, encoding 239 and 238 amino acids, respectively. Both the MiCAL1 and MiCAL2 proteins contained typical MADS-box and K-box domains and therefore belonged to the CAL-like protein family. MiCAL1 and MiCAL2 were expressed in all tissues at the inflorescence elongation stage and flowering stage, with the highest expression in the leaves at the flowering stage. They had similar expression patterns during flower development, with the highest expression levels in leaves during flower differentiation and the lowest expression levels during fruit development. Overexpression of MiCAL1 and MiCAL2 resulted in significantly earlier flowering in Arabidopsis. Overexpression of MiCAL1 resulted in terminal flowers with normal flower organs, while overexpression of MiCAL2 induced partially variation in floral organs but had no effect on inflorescences. Yeast two-hybrid (Y2H) experiments showed that MiCAL1 and MiCAL2 can interact with several flower-related proteins as well as stress response proteins, such as SEP1, SVP1, SVP2, SOC1G and Di19-4. These results suggest that these two MiCALs genes may have an important influence on mango flowering. [ABSTRACT FROM AUTHOR]

The CONSTANS-LIKE1 (COL1) gene plays an important role in the regulation of photoperiodic flowering in plants. In this study, two COL1 homolog genes, MiCOL1A and MiCOL1B, were isolated from mango (Mangifera indica L.). The open reading frames of MiCOL1A and MiCOL1B are 852 and 822 bp in length and encode 284 and 274 amino acids, respectively. The MiCOL1A and MiCOL1B proteins contain only one CCT domain and belong to the CO/COL group IV protein family. MiCOL1A and MiCOL1B were expressed both in vegetative and reproductive organs but with expression level differences. MiCOL1A was highly expressed in juvenile and adult leaves, but MiCOL1B was highly expressed in flowers. Seasonal expression analysis showed that MiCOL1A and MiCOL1B have similar expression patterns and higher expression levels during flower induction and flower organ differentiation periods. However, MiCOL1A and MiCOL1B exhibited unstable patterns in circadian expression analysis. MiCOL1A and MiCOL1B were localized in the nucleus and had transcriptional activation activity in yeast. Overexpression of MiCOL1A and MiCOL1B resulted in significantly delayed flowering time in Arabidopsis. Furthermore, we also found that overexpression of MiCOL1A and MiCOL1B enhanced drought tolerance in transgenic Arabidopsis. The results demonstrated that MiCOL1A and MiCOL1B are not only involved in flowering regulation but also play a role in the stress response of plants. • Two MiCOL1 genes MiCOL1A and MiCOL1B were isolated from mango. • MiCOL1A was mainly expressed in juvenile and adult leaves, MiCOL1B in flowers. • MiCOL1 proteins are localized in the nucleus and have transcriptional activity. • Overexpression of MiCOL1 in Arabidopsis led to delayed flowering. • Overexpression of MiCOL1 in Arabidopsis led to stronger tolerance to drought. [ABSTRACT FROM AUTHOR]

FLOWERING LOCUS T (FT) is a key integrator of environmental signals and internal cues and plays a central role in the photoperiod response mechanism in Arabidopsis. However, the function of FTs in Mangifera indica L. is unknown. In this study, we identified three MiFTs genes from mango and characterized their role in flowering regulation. The open reading frames of MiFT1 , MiFT2 , and MiFT3 are 540, 516, and 588 bp in length and encode 180, 172, and 196 amino acids, respectively; the genes belong to the PEBP family. MiFTs share the conserved exon/intron structure of FTs. The nucleotide sequence of MiFT1 is 90% identical to that of MiFT2 and 82% identical to that of MiFT3 ; MiFT2 and MiFT3 share 81% homology with each other. According to expression analysis, MiFTs were detected at different expression levels in all tested tissues. The expression levels of the three MiFTs were significantly different in leaves during flower development, and MiFT1 expression increased sharply in leaves and was significantly higher than that of the other two MiFTs during flower bud development. All three MiFTs showed daily cycles. Ectopic expression of the three MiFTs in transgenic Arabidopsis resulted in an earlier flowering genotype under long-day conditions, and MiFT1 had the strongest effect in promoting flowering. Additionally, overexpression of three MiFTs in Arabidopsis upregulated the expression levels of several flowering-related genes. Our results suggest that the three MiFTs have positive roles in promoting flowering and suggest that MiFT1 may acts as a key regulator in the flowering pathway. • 1, Three MiFTs genes MiFT1 , MiFT2 , and MiFT3 were cloned from mango. • 2, MiFT1 was highly expressed in adult leaves, MiFT2 in adult stems and MiFT3 in adult leaves and flowers. • 3, Expression profiles of MiFTs were regulated by diurnal rhythm. • 4, Overexpression of three MiFTs in Arabidopsis resulted in early flowering. • 5, MiFT1 may encode a florigen that acts as a key regulator in the mango flowering. [ABSTRACT FROM AUTHOR]

The CO/COL gene family plays an important role in regulating photoperiod-dependent flowering time in plants. In this study, two COL2 gene homologs, MiCOL2A and MiCOL2B, were isolated from 'SiJiMi' mango, and their expression patterns and functions were characterized. The MiCOL2A and MiCOL2B genes both belonged to the group Ⅰ of CO/COL gene family. MiCOL2A and MiCOL2B exhibited distinct circadian rhythms and were highly expressed in leaves during the flowering induction period. Subcellular localization analysis revealed that MiCOL2A and MiCOL2B are localized in the nucleus. The overexpression of MiCOL2A and MiCOL2B significantly delayed flowering time in Arabidopsis under both long-day (LD) and short-day (SD) conditions. The MiCOL2A and MiCOL2B overexpression Arabidopsis plants exhibited more tolerance to slat and drought stress after abiotic stress treatments, with greater ROS scavenging capacity and protective enzyme activity, less cell damage and death and higher expression of stress response genes than wild type plants. Bimolecular fluorescence complementation (BiFC) analysis showed that MiCOL2A and MiCOL2B interacted with several stress-related proteins, including zinc finger protein 4 (MiZFP4), MYB30-INTERACTING E3 LIGASE 1 (MiMIEL1) and RING zinc finger protein 34 (MiRZFP34). The results indicate that MiCOL2A and MiCOL2B are not only involved in flowering time but also play a positive role in abiotic stress responses in plants. • Two CONSTANS-like 2 genes were cloned from mango. • The expression patterns of the CONSTANS-like 2 genes were analysed in mango. • Overexpression of two CONSTANS-like 2 in Arabidopsis resulted in delayed flowering. • Overexpression of two CONSTANS-like 2 enhanced the salt and drought stress tolerance in transgenic Arabidopsis. [ABSTRACT FROM AUTHOR]