Oligomeric Proanthocyanidins (OPCs), as a class of compounds widely found in plants, are particularly abundant in grapes and blueberries. It is a polymer comprising many different monomers, such as catechins and epicatechins. The monomers are usually linked to each other by two types of links, A-linkages (C-O-C) and B-linkages (C-C), to form the polymers. Numerous studies have shown that compared to high polymeric procyanidins, OPCs exhibit antioxidant properties due to the presence of multiple hydroxyl groups. This review describes the molecular structure and natural source of OPCs, their general synthesis pathway in plants, their antioxidant capacity, and potential applications, especially the anti-inflammatory, anti-aging, cardiovascular disease prevention, and antineoplastic functions. Currently, OPCs have attracted much attention, being non-toxic and natural antioxidants of plant origin that scavenge free radicals from the human body. This review would provide some references for further research on the biological functions of OPCs and their application in various fields.

The plant hormone abscisic acid (ABA) has been proved to be a key protector against abiotic stresses at appropriate concentrations. This study aimed to investigate the role of ABA in alleviating cadmium (Cd) stress in two Brassica napus of oil-vegetable dual-purpose (Youfei 1 and Xiangyou 787). Cd stress disturbed the normal growth of rapeseed, however, specific ABA concentrations could alleviate the effects of Cd stress in B. napus. The results confirmed that exogenous ABA mitigates the negative effects of Cd-induced plant toxicity in B. napus by increasing growth traits, enhancing pigment molecules, enhancing gas exchange in leaves, as well as regulating antioxidation and the expression levels of genes related to Cd stress. This study indicated that ABA played an important protective role in regulating cadmium resistance in Brassica napus, and provided basic data for its application in actual production.

The contamination of soil with high levels of cadmium (Cd) is of increasing concern, as Cd is a heavy metal element that seriously limits crop productivity and quality, thus affecting human health. (1) Background: Some miRNAs play key regulatory roles in response to Cd stress, but few have been explored in the highly Cd-enriched coefficient oilseed crop, Brassica juncea. (2) Methods: The genome-wide identification and characterization of miRNAs and their targets in leaves and roots of Brassica juncea exposed to Cd stress was undertaken using strand specific transcript sequencing and miRNA sequencing. (3) Results: In total, 11 known and novel miRNAs, as well as 56 target transcripts, were identified as Cd-responsive miRNAs and transcripts. Additionally, four corresponding target transcripts of six miRNAs, including FLA9 (Fasciclin-Like Arabinogalactan-protein 9), ATCAT3 (catalase 3), DOX1 (dioxygenases) and ATCCS (copper chaperone for superoxide dismutase), were found to be involved in the plant’s biotic stress pathway. We further validated the expression of three miRNA and six target genes in response to Cd, hydrargyrum (Hg), manganese (Mn), plumbum (Pb) or natrium (Na) stress and Mucor infection by qRT-PCR, and show that ATCCS and FLA9 were significantly and differentially regulated in the Cd-treated leaves. In addition, our results showed that DOX1 was obviously induced by Pb stress. Among the respective target miRNAs, bra-miR172b-3p (target for ATCCS) and ra-miR398-3p (target for FLA9) were down-regulated in Cd-treated leaves. (4) Conclusions: We identified bra-miR172b-3p as a potential Cd-specific resistant inhibitor, which may be negatively regulated in ATCCS in response to Cd stress. These findings could provide further insight into the regulatory networks of Cd-responsive miRNA in Brassica juncea.

The VQ motif-containing proteins play a vital role in various processes such as growth, resistance to biotic and abiotic stresses and development. However, there is currently no report on the VQ genes in sugarcane (Saccharum spp.). Herein, 78 VQ genes in Saccharum spontaneum were identified and classified into nine subgroups (I-IX) by comparative genomic analyses. Each subgroup had a similar structural and conservative motif. These VQ genes expanded mainly through whole-genome segmental duplication. The cis-regulatory elements (CREs) of the VQ genes were widely involved in stress responses, phytohormone responses and physiological regulation. The RNA-seq data showed that SsVQ gene expression patterns in 10 different samples, including different developmental stages, revealed distinct temporal and spatial patterns. A total of 23 SsVQ genes were expressed in all tissues, whereas 13 SsVQ genes were not expressed in any tissues. Sequence Read Archive (SRA) data showed that the majority of SsVQs responded to cold and drought stress. In addition, quantitative real-time PCR analysis showed that the SsVQs were variously expressed under salicylic acid (SA), jasmonic acid (JA), abscisic acid (ABA) and cold treatment. This study conducted a full-scale analysis of the VQ gene family in sugarcane, which could be beneficial for the functional characterization of sugarcane VQ genes and provide candidate genes for molecular resistance breeding in cultivated sugarcane in the future.

Concentrations of heavy metals continue to increase in soil environments as a result of both anthropogenic activities and natural processes. Cadmium (Cd) is one of the most toxic heavy metals and poses health risks to both humans and the ecosystem. Herein, we explore the impacts of Cd on a soil–plant system composed of oilseed rapes (Brassica napus and Brassica juncea) and bacteria. The results showed that Cd accumulation within tissues of two species of oilseed rapes enhanced with increasing concentrations of Cd in soils, and Cd treatment decreased their chlorophyll content and suppressed rapeseeds growth. Meanwhile, Cd stress induced the changes of antioxidative enzymes activities of both B. napus and B. juncea. Response to Cd of bacterial community was similar in soil-two species of oilseed rapes system. The impact of Cd on the bacterial communities of soils was greater than bacterial communities of plants (phyllosphere and endophyte). The α-diversity of bacterial community in soils declined significantly under higher Cd concentration (30 mg/kg). In addition, soil bacterial communities composition and structure were altered in the presence of higher Cd concentration. Meanwhile, the bacterial communities of bulk soils were significantly correlated with Cd, while the variation of rhizosphere soils bacterial communities were markedly correlated with Cd and other environmental factors of both soils and plants. These results suggested that Cd could affect both the growth of plants and the indigenous bacterial community in soil–plant system, which might further change ecosystem functions in soils.

FHY3 and FAR1 serve as positive regulators of the phyA-mediated far-red light signal pathway, influencing plant growth and development by regulating the expression of downstream genes. However, little is known about the FAR1/FHY3 family in Brassica species. A total of 21 members of the BnFAR1/FHY3 gene family were identified in the Brassica napus genome, exhibiting an uneven distribution across ten B. napus chromosomes. A phylogenetic analysis showed that the BnFAR1/FHY3 family could be divided into four subfamilies. Putative cis-elements in the BnFAR1/FHY3 promoter regions were also identified, which were potentially involved in phytohormone, light and abiotic stress responses (shading, low-temperature, etc.). Additionally, qRT-PCR results indicated that the expression levels of BnFAR1-10, BnFAR1-11, BnFAR1-21 and BnFAR1-4 decreased under shading stress. The expression of BnFAR1-10, BnFAR1-11 and BnFAR1-21 increased under low-temperature stress, whereas the expression of BnFAR1-4 did not change. In addition, the results of the tissue expression analysis showed that most of the genes exhibited the lowest expression in pollen and the highest expression in the 54-day silique. This study screened a batch of BnFHY3/BnFAR1 gene resources, which will contribute to further research on the functional characteristics of BnFHY3/BnFAR1 family members in growth, development and the stress response.