Rubus tingzhouensis C.An & G.C.Lin, a newly-defined species within the family Rosaceae from Fujian Province, China, is formally described and illustrated here. R. tingzhouensis is morphologically similar to R. swinhoei, but can be distinguished by several key characteristics, such as long, reddish-purple stipitate glands, soft bristles, light yellow short trichomes (vs. shortly grey tomentose at the early stage, glabrescent) and scattered epidermal prickles (vs. few to many curved prickles). Furthermore, the stipules are pinnately deeply laciniate, measuring 1–1.5 cm (vs. ovate-oblong to ovate-lanceolate, 0.5–0.8 cm). Phylogenetic analyses, based on partial sequences and the complete plastome data, provide robust support for a close relationship between R. tingzhouensis and R. swinhoei, while also highlighting distinct genetic differentiation between these two species. The chloroplast genome of R. tingzhouensis is 156,311 bp in length and comprises 132 unique genes, including 86 protein-coding genes, 37 transfer RNAs, eight ribosomal RNAs and one pseudogene.

Passion fruit, an economically valuable fruit crop, is highly vulnerable to adverse climate conditions. The HVA22 genes, recognized as abscisic acid (ABA) and stress-inducible, play vital roles in stress response and growth regulation in diverse eukaryotic organisms. Here, six HVA22 genes were firstly identified in passion fruit genome and all predicted to be localized within the endoplasmic reticulum. Phylogenetic analyses showed that all PeHVA22s were divided into four subgroups. The gene structural features of PeHVA22 genes clustered in the same subgroup were relatively conserved, while the gene structure characteristics of PeHVA22s from different subgroups varied significantly. PeHVA22A and PeHVA22C closely clustered with barley HVA22 in Group II, were also induced by ABA and drought stress treatment, suggesting conserved roles similar to barley HVA22. Meanwhile, most PeHVA22s exhibited induced expression post-drought treatment but were suppressed under salt, low and high-temperature conditions, indicating a unique role in drought response. Additionally, PeHVA22s displayed tissue-specific expression patterns across diverse tissues, except for PeHVA22B which maybe a pseudogene. Notably, PeHVA22C, PeHVA22E, and PeHVA22F predominantly expressed in fruit, indicating their involvement in fruit development. Almost all PeHVA22s showed variable expression at different developmental stages of stamens or ovules, implying their roles in passion fruit’s sexual reproduction. The intricate roles of PeHVA22s may result from diverse regulatory factors including transcription factors and CREs related to plant growth and development, hormone and stress responsiveness. These observations highlighted that PeHVA22s might play conserved roles in ABA response and drought stress tolerance, and also be participated in the regulation of passion fruit growth and floral development.

Passion fruit, a valuable tropical fruit, faces climate-related growth challenges. Antioxidant enzymes are vital for both stress protection and growth regulation in plants. We first provided systemic analysis of enzymatic antioxidant gene families in passion fruit, identifying 90 members including 11 PeSODs, 45 PeAPXs, 8 PeCATs, 7 PeGPXs, 6 PeMDHARs, 8 PeDHARs, and 5 PeGRs. Gene members in each gene family with same subcellular localization showed closer phylogenetic relationship. Many antioxidant genes exhibited tissue- or developmental stage-specific expression patterns during floral and fruit development, with some widely expressed. Their co-expressed genes were linked to photosynthesis and energy metabolism, suggesting roles in protecting highly proliferating tissues from oxidative damage. Potential genes for enhancing temperature stress resistance were identified. The involvement of diverse regulatory factors including miRNAs, transcription factors, and CREs might contribute to the complex roles of antioxidant genes. This study informs future research on antioxidant genes and passion fruit breeding.

Passion fruit (Passiflora edulis) is an economically valuable tropical fruit crop renowned for its nutritious juice, aromatic fragrance, and vibrant flowers with distinct floral structure, known as corona. These unique floral features make passion fruit a good candidate for the study of floral organogenesis. MADS-box genes play essential functions in various aspects of plant growth and development, especially for floral morphogenesis. However, a comprehensive investigation of MADS-box gene family members in passion fruit has not yet been conducted. Here, 52 MADS-box genes were identified in the passion fruit genome and classified into two types with five subgroups (type I: Mα, Mβ, Mγ; type II: MIKC^C, MIKC*) based on phylogeny. The notable reduction in the abundance of type I MADS-box genes within the passion fruit genome, in contrast to Arabidopsis, is thought to be a contributing factor to the diminished gene number within this gene family. The structural analysis illustrated that PeMADS proteins within the same subfamily are relatively conserved. Moreover, we proposed the putative flower regulation ABC(D)E model of passion fruit and explored the regulatory genes of the characteristic structure corona. We found that the regulation of petals and stamens in passion fruit is similar to that of Arabidopsis, but differs in terms of carpels and sepals. The distinct coronas were predominately controlled by B-, C(D)- and E-class genes, supporting the speculation that the corona might have originated from stamens. Except for the core functions in the floral meristem, many PeMADS genes were also involved in the development regulation of non-floral tissues and/or in phytohormone and stress responses. The co-presence of diverse cis-regulatory elements associated with growth/developmental regulation, phytohormone and stress responses in the promoter regions of PeMADSs might be closely related to their diverse regulatory roles. The results of this study provide valuable insights into the MADS-box genes in passion fruit and their involvement in the development of floral structure. These discoveries lay the foundation for the cultivation of exceptional ornamental varieties of passion fruit.