Cassava (Manihot esclenta Crantz) has excellent planting characteristics such as drought resistance, barren tolerance and strong adaptability, and is the main food crop for more than 1 billion people in the world. CMLs (calmodulin-like proteins) are plant calmodulin-like receptors in cells. They interact with other calmodulin-binding proteins to regulate cellular physiological processes and participate in plant stress response. MeCML42 gene in cassava is induced by drought stress. In order to study the drought stress response pathway involved in this gene, yeast two-hybridization was used to screen the interacting proteins of MeCML42. Firstly, the decoy vector pGBKT7-MeCML42 was constructed by homologous recombination technique, and the self-activation experiment showed that MeCML42 protein had no self-activation activity. The toxicity test showed that MeCML42 protein was not toxic to yeast and did not affect the normal growth of yeast. The cDNA library was screened by yeast two-hybridization and 7 candidate interacting proteins were obtained. The interaction between MeCML42 and thioredoxin MeCDSP32 was verified by yeast double heterogyclic experiment. Mannitol simulation of drought stress showed that the expressions of MeCML42 and MeCDSP32 were both induced by drought, and the expression levels were the highest at 48 h under stress. These results indicated that MeCML42 and MeCDSP32 were synergistically involved in cassava's response to drought stress. The results of this study provide a new basis for MeCML42 to participate in cassava response to drought stress.

Phytochelatin synthase (PCS) is a key enzyme that catalyzes the synthesis of phytochelatin (PC). PC can reduce the toxicity of heavy metals to plants through complexation. Heavy metal pollution in soil increases the risk of cassava food safety. It is of great significance to study the reduction and control of heavy metals in cassava by analyzing the function of MePCS1 gene. In this study, the coding region of MePCS1 gene in cassava variety SC8 was cloned by PCR. The full length was 1512 bp, encoding 503 amino acids. Protein sequence analysis showed that MePCS1 protein was a hydrophilic protein, containing 41 phosphorylation sites and 2 glycosylation sites, without signal peptide. The phylogenetic tree showed that the cassava MePCS1 protein had the closest relationship with the PCS protein of the rubber tree. The qPCR analysis showed that the MePCS1 gene had the highest expression level in the stem. During the development of cassava roots, the expression level of MePCS1 gene was the highest in the root enlargement period. Lead (Pb) stress induced MePCS1 gene expression. MePCS1 gene can improve the tolerance of BY4741 yeast to Pb. The results of this study provide new information for further analysis of the functional characteristics of the MePCS1 gene and its mechanism for reducing Pb in cassava tuber roots.

The plant resources from nine islands of Xisha Yongle Islands and Xuande Islands (including Yongxing Island, Shi Island, Zhaoshu Island, Dong Island, Zhongjian Island, Jinyin Island, Chenhang Island, Guangjin Island and Shanhu Island) were surveyed in 2021 to 2023. Through field survey, specimen collection and identification, and literature review, 11 plants belonging to 10 genera in 8 families were recorded for the first time. The voucher specimens are deposited in the herbarium of Chinese Academy of Tropical Agricultural Sciences (ATCH). This study would provide important information for the plant resources of Xisha Islands.

Yinggeling area of the National Park of Hainan Tropical Rainforest preserves the largest and most intact tropical rainforest in South China. It is extraordinarily rich in fungal species, especially the fungi of Boletales with important ecological, scientific and economic values. Nearly 300 specimens of Boletales were collected from Yinggeling area in the past 10 years. On the basis of morphology, molecular phylogenetic analyses, ecological characteristics, and geographical information, a total of 82 species of Boletales, belonging to 37 genera and 5 families, have been identified. Among them, 2 genera and 26 species were typified from Yinggeling, 2 were new to China, and 20 were new to Hainan Province. In the Boletales in Yinggeling area, the only dominant family, with more than 10 species, was Boletaceae, accounting for 91.46% of the total species. There were 6 dominant genera (Aureoboletus, Boletellus, Neoboletus, Phylloporus, Strobilomyces, and Tylopilus), with more than 5 species, haboring 48.78% of the total species of this Order. Among the Boletales species from Yinggeling area, 20, 4, and 8 are considered to be edible, medicinal and poisonous mushrooms, respectively.

The CUT&Tag technology is a new method for protein-DNA interactions, which uses a novel pG-Tn5 transposase with ultra-high activity, to precisely target and cleave DNA sequences near the target protein under antibody guidance, thus enabling cDNA library construction and sequencing analysis. This technology is widely used in human and animal research, but due to the unique structure of plant cells, its application in plant research is relatively limited. In previous studies, we found histone acetylation can participate in the regulation of jasmonic acid induced secondary laticifer differentiation, but the molecular mechanism of histone acetylation modification regulating secondary laticifer differentiation has not been elucidated in rubber tree. In this article, we used the experimental system of secondary laticifer differentiation induced by cornetin (COR) in the vascular cambium by the CUT&Tag technology, and the high quality protoplasts of cambium cells were obtained by enzymolysis, and the Histone H3 acetylation modified antibody was used to identify in situ the region of histone acetylation modification during secondary laticifer differentiation. A cDNA library of cambium cells treatment by COR was successfully constructed using CUT&Tag technology in rubber tree bark. Quality inspection and sequencing analysis were conducted on the construction of cDNA libraries, and found that the quality of libraries were good. And GO and KEGG enrichment analysis of differential genes found the genes related to auxin, flavonoid metabolism, and protein ubiquitination were enriched. The results would provide an operational method for constructing cDNA libraries of plant tissues using CUT&Tag technology, and provide a theoretical basis for elucidating the molecular mechanism of histone acetylation modification regulating secondary laticifer differentiation in rubber tree.

MinD is involved in the fine regulation of plastid division and plays a key role in maintaining plastid morphology. Previous laboratory research found that the MeMinD protein is involved in the division of cassava plastids, but the related proteins that work in conjunction with MeMinD to regulate the division of cassava plastids have not been clearly identified. This study constructed the pGBKT7-MeMinD vector and, through yeast two-hybrid library screening, a total of 8 candidate interacting proteins of MeMinD were obtained; after point-to-point verification using the yeast two-hybrid system, it was found that the nicotinate phosphoribosyltransferase 2 (MeNAPRT2) interacts with MeMinD. The results of this study would provide new information for further analysis of the mechanism of MeMinD's participation in the regulation of cassava plastid splitting.

Understanding the expression regulation mechanisms of enzymes related to starch synthesis in cassava can significantly advance the molecular breeding for high yield and high starch content. Prior research has uncovered that the auxin-responsive gene, MeSAUR1, upregulates the expression of MeAGPS1a, a gene encoding the small subunit of the key starch-synthesizing enzyme, AGPase. Yeast two-hybrid screening identified a Yippee protein family member, MeYippee1, as a candidate interacting protein with MeSAUR1. In this study, the coding region of the MeYippee1 gene from cassava variety SC8 was cloned. The gene was 321 bp in the coding region, lacking introns, encoding a protein of 106 amino acids, with four predicted phosphorylation sites. Expression analysis in different tissues and organs revealed that MeYippee1 was most highly expressed in axillary buds, followed by fibrous roots, storage roots, and mature leaves, while expression levels were lower in stems and petioles, and the lowest in apical buds and young leaves. Expression analysis during the different developmental stages of the storage root showed that MeYippee1 expression was primarily during the formation phase of the storage roots. Further point-to-point yeast two-hybrid verification indicated an interactive relationship between MeYippee1 and MeSAUR1 proteins. The results would provide new insights into the molecular mechanism underlying the positive regulation of MeAGPS1a expression by MeSAUR1.

Thioredoxin (TRX), a redox regulatory protein, plays an important role in plant resistance to abiotic stress. In this study, HbTRXo2, a thioredoxin gene, was cloned from rubber tree (Hevea brasiliensis) using RT-PCR. HbTRXo2 contained a coding region of 594 bp encoding a protein of 197 amino acids. The predicted molecular weight and isoelectric point of HbTRXo2 was 21.90 kDa and 7.59, respectively. The conserved domain and phylogenetic analysis showed that HbTRXo2 had a conserved TRX domain and was clustered with other plant o-type thioredoxin, suggesting that HbTRXo2 belonged to o-type thioredoxin. Quantitative real-time PCR indicated that HbTRXo2 gene was expressed in root, bark, latex, mature leaf, senescent leaf, new shoot, female flower and male flower tissues of rubber tree, with significantly higher expression level in latex than in other tissues. Compared with the healthy rubber trees, the expression of HbTRXo2 in the bark and latex of tapping panel dryness trees was significantly reduced. Under cold, polyethylene glycol (PEG)-induced drought, and oxidative stress induced by hydrogen peroxide (H₂O₂) and methyl violet (MV), the expression of HbTRXo2 gene was significantly up-regulated, indicating the involvement of HbTRXo2 in response to abiotic stress in rubber tree. To explore the function of HbTRXo2 in stress resistance, its yeast expression vector was constructed and transferred into Saccharomyces cerevisiae INVSC1 to obtain the recombinant yeast INVSC1 (pYES2-HbTRXo2). The survival differences between the recombinant yeast INVSC1 (pYES2-HbTRXo2) and the control yeast INVSC1 (pYES2) transformed with pYES2 empty vector after H₂O₂, PEG, and low temperature stress treatments were compared, and the results showed that the survival rate of INVSc1 (pYES2-HbTRXo2) was significantly higher than that of INVSC1 (pYES2) after PEG and H₂O₂ treatments, while the survival rate of INVSc1 (pYES2-HbTRXo2) was significantly lower than that of INVSC1 (pYES2) after low temperature stress treatment, indicating that the recombinant yeast transformed with HbTRXo2 gene improved the resistance to drought and oxidative stresses, but decreased the resistance to low temperature stress. The results demonstrate that HbTRXo2 plays an important role in latex production and latex flow, as well as abiotic stress resistance in rubber tree. The study would provide important references for further elucidating the biological function of HbTRXo2 in rubber trees.

Litchi (Litchi chinensis Sonn.) is one of the important economic crops in subtropical areas. However, it is difficult to store litchi after picking and easy to browning, which is one of the biggest problems in the preservation process. WRKY family is a common transcription factor in plants, which mainly regulates physiological processes such as plant stress response and maturation. In order to research the effect of WRKY on the ripening and senescence process of litchi fruit after harvest, this study took Feiziao litchi as the experimental object, and cloned LcWRKY47 gene. The gene length was 1077 bp. The protein contains WRKY conserved domain. The secondary structure is dominated by random curling, accounting for 65.64%, and the tertiary structure is dominated by random curling and α-helix. Through motif analysis and multiple sequence alignment, LcWRKY47 protein was found to be a class II WRKY transcription factor. Phylogenetic analysis showed that LcWRKY47 in litchi was closely related to DlWRKY47 in longan, which are all classified as Sapindaceae. Subcellular localization experiments showed that LcWRKY47 protein was localized in the nucleus. RT-qPCR analysis showed that after treatment with 2 mmol/L oxalic acid, the expression of LcWRKY47 gene in the peel and pulp of litchi showed the same trend, which increased first and then decreased, and the expression level of LcWRKY47 gene in the treatment group was significantly higher than that in the control group after storage, suggesting that this transcription factor plays a positive role in the regulation of oxalic acid in the ripening and senescence process of litchi fruit. Overexpression of LcWRKY47 gene showed that the expression level of LcWRKY47 in transgenic fruits was significantly higher than that in control fruits, and the senescence process and browning of transgenic litchi was significantly better than that in treatment group. In conclusion, LcWRKY47 transcription factor may play a regulatory role in the senescence and browning process of litchi.

Mango is a typical respiration leap fruit, with vigorous postharvest metabolism and very sensitive to ethylene.CTR1 is a negative regulator of the ethylene signaling pathway and plays a central role in the ethylene signaling pathway. In order to study the possible role of mango CTR1 expression pattern in mango postharvest storage, a CTR gene (MiCTR1) was screened from the Tainung No.1) mango transcriptome database, and its encoded gene was used using biological methods. The protein was sequenced and analyzed, and the expression pattern of MiCTR1 gene during mango ripening and under 1-MCP treatment was analyzed. The results showed that the length of the open reading frame of MiCTR1 was 1551 bp, encoding 516 amino acids, The molecular formula of the predicted protein was C₂₅₀₃H₃₉₃₂N₇₁₂O₇₉₇S₂₆, the total atomic number was 7970, and the weight of the protein was 57.58 kDa, the theoretical isoelectric point (pI) was 5.72, the fat coefficient was 70.78, and the overall average hydrophilicity was -0.596, with 111 phosphorylation sites, and the phosphorylation modification of serine was the main one, supplemented by threonine, had no transmembrane structure and no signal peptide. Subcellular prediction analysis showed that it was located in the nucleus. Protein domain prediction MiCTR1 protein contained a conserved PB1 domain located at amino acid sequence 189-285. Phylogenetic analysis showed that MiCTR1 was closely related to Prunus dulcis, Prunus persica, Prunus avium, Prunus armeniaca, Prunus mume. The results of fluorescence quantitative PCR showed that the relative expression of MiCTR1 increased during the ripening process of mango, and 1-MCP down-regulated its expression. In this study, the MiCTR1 gene was cloned in mango and its biological analysis was analyzed, and its expression pattern during postharvest storage was analyzed, which would provide a basis for the molecular mechanism of mango ripening.