The interaction between light and phytohormones is crucial for plant growth and development. The practice of supplementing light at night during winter to promote pitaya flowering and thereby enhance yield has been shown to be crucial and widely used. However, it remains unclear how supplemental winter light regulates phytohormone levels to promote flowering in pitaya. In this study, through analyzing the transcriptome data of pitaya at four different stages (NL, L0, L1, L2), we observed that differentially expressed genes (DEGs) were mainly enriched in the phytohormone biosynthesis pathway. We further analyzed the data and found that cytokinin (CK) content first increased at the L0 stage and then decreased at the L1 and L2 stages after supplemental light treatment compared to the control (NL). Gibberellin (GA), auxin (IAA), salicylic acid (SA), and jasmonic acid (JA) content increased during the formation of flower buds (L1, L2 stages). In addition, the levels of GA, ethylene (ETH), IAA, and abscisic acid (ABA) increased in flower buds after one week of development (L2f). Our results suggest that winter nighttime supplemental light can interact with endogenous hormone signaling in pitaya, particularly CK, to regulate flower bud formation. These results contribute to a better understanding of the mechanism of phytohormone interactions during the induction of flowering in pitaya under supplemental light in winter.

Self-incompatible pitaya varieties have low fruit-setting rates under natural conditions, leading to higher production costs and hindering industrial prosperity. Through transcriptome sequencing, we obtained the 36,900 longest transcripts (including 9167 new transcripts) from 60 samples of flowers. Samples were collected pre- and post-pollination (at 0 h, 0.5 h, 2 h, 4 h, and 12 h) from two varieties of pitaya (self-compatible Jindu No. 1 and self-incompatible Cu Sha). Using the RNA-Seq data and comparison of reference genomes, we annotated 28,817 genes in various databases, and 1740 genes were optimized in their structure for annotation. There were significant differences in the expression of differentially expressed genes (DEGs) in the pitaya stigmas under different pollination types, especially at the late post-pollination stage, where the expression of protease genes increasedal significantly under cross-pollination. We identified DEGs involved in the ribosomal, ubiquitination-mediated, and phyto-signaling pathways that may be involved in pitaya SI regulation. Based on the available transcriptome data and bioinformatics analysis, we tentatively identified HuS-RNase2 as a candidate gynogenetic S gene in the pitaya GSI system.

Durian is highly sensitive to chilling temperatures, which restrict its cultivation beyond tropical regions. In this study, one-year-old seedlings of the cultivars ‘Musang King’ and ‘Monthong’ were exposed to 10 °C for 7 days to characterize their phenotypic, physiological, and transcriptional responses. Leaf phenotype, membrane injury, osmotic adjustment, photosynthetic pigment contents, amylase activity, and antioxidant enzyme activities were evaluated, and transcriptome sequencing was performed using samples collected before chilling treatment and after 1 and 5 days of exposure. ‘Monthong’ exhibited earlier and visually more extensive leaf abscission than ‘Musang King’, while the two cultivars showed contrasting temporal patterns of malondialdehyde accumulation and antioxidant enzyme activities. Comparative transcriptome analysis was subsequently used to construct a Musang King-focused discovery set comprising genes prioritized based on progressive induction patterns and higher transcript abundance in ‘Musang King’. Because AP2/ERF transcription factors were represented in this discovery set, the DREB gene family was characterized at the whole-genome level. A total of 81 DzDREB genes were identified and classified into six subgroups. Integration of transcriptomic response patterns, stress-related functional annotations, and promoter cis-regulatory elements supported the prioritization of a ten-gene DzDREB panel for further investigation. Exploratory seasonal field-expression profiling provided additional support for seven candidates, among which DzDREB36, DzDREB45, DzDREB62, and DzDREB66 showed comparatively stronger support across datasets. These results provide candidate resources for further functional investigation of differential chilling responses in durian.

Durian (Durio zibethinus) germplasm may be incorrectly named, mislabeled, or genetically misidentified during introduction, exchange, and nursery stock distribution. Morphological identification is also affected by environmental conditions and plant developmental stages. A core simple sequence repeat (SSR) marker set was developed for the identification of durian germplasm. Genome-wide mining identified 106,776 SSR loci in the durian reference genome, and 18 stable and polymorphic markers were selected from 160 candidate primer pairs through agarose gel screening and M13-tailed fluorescent capillary electrophoresis. A total of 142 alleles were detected at the 18 SSR loci across the 58 durian accessions, with 3–15 alleles per locus and PIC values ranging from 0.422 to 0.849. Exhaustive evaluation of all marker combinations identified a minimum six-locus core SSR marker set comprising Y6, Y12, Y15, Y75, Y91, and Y108, which generated unique multilocus genotypes for all 58 accessions in the current validation panel, with a cumulative probability of identity (PID) of 7.99 × 10⁻⁸. STRUCTURE analysis, with K representing the number of inferred genetic clusters, supported K = 8 and revealed admixture in several accessions. The core SSR marker set developed in this study can distinguish the 58 durian accessions and be used to construct their DNA fingerprints. Validation in larger and more genetically diverse germplasm collections is required before routine commercial deployment.