Citrus is usually considered as a typical non-climacteric fruit，with abscisic acid being primarily associated with citrus fruit maturity. However，other hormones，such as ethylene，gibberellin，auxin，also contribute significantly to the maturity and color transition of citrus. In production，a variety of natural hormones and synthetic plant growth regulators are commonly utilized to extend the marketing period of citrus fruits and improve postharvest preservation. This paper provides a comprehensive review of current research advances concerning the role of plant hormones on the maturation of citrus fruits. It delves into the complex relationships between these hormones and investigates the regulatory mechanisms controlled by related transcription factors. The primary aim is to provide reference for further research.

In this study，Camellia sinensis phytoene desaturase gene（CsPDS）and tea caffeine synthase gene（TCS1）as indicator genes and Nicotiana benthamiana as a vector were employed to enrich tobacco rattle virus. The effects of the concentration of infiltration solution，incubation temperature，different vectors and incubation time on the enriched viruses were investigated，with N. benthamiana used as the vector to enrich the viruses. The effects of different inoculation methods and cultivars on the construction of a virus-induced gene silencing（VIGS）system were also investigated in tea plant. The results demonstrated that inoculation of tobacco with acetosyringone（AS）at a concentration of 200 μmol · L^-1 bacteriophage with an optical density（OD₆₀₀）of 1.0 was conducive to virus enrichment in tobacco when incubated at 23 ℃. The leaves of‘Shuchazao’were used to construct the VIGS system of tea plant by injection inoculation, and the system was successfully used to explore the possibility of foreign gene expression with GFP as the indicator gene.

In this study，high temperature experiment was conducted and phylogenetic index were analyzed using Rosa chinensis‘Angela’‘Renyue’and‘Xianjing’as test materials. The results showed that‘Angela’exhibited the highest heat resistance among the three varieties. Comparative transcriptome analysis，co-expression network analysis，protein-protein interaction network analysis and phylogenetic analysis revealed that the improvement of heat tolerance in‘Angela’is associated with the overexpression of heat shock transcription factors（HSFs）and heat shock proteins（HSPs）. Notably，the expression level of HSP gene RcHSP18.1 significantly increased with prolonged heat stress duration. Furthermore，by silencing the homologous gene NtHSP18.1 in tobacco，the heat resistance of tobacco was significantly reduced，confirming the essential role of HSP18.1 in heat stress tolerance. Overexpressing of RcHSP18.1 through gene bombardment and silencing RcHSP18.1 gene by virus induced gene silencing technique have both confirmed the significant role the gene RcHSP18.1 in enhancing heat stress resistance in‘Angela’.

In this study，by using Ziziphus jujuba‘Dongzao’as a model，the phenological phases of flower development were documented，the process of flower development and nectar secretion was tracked，and the quantity and sugar content of the nectar were assessed under the facility cultivation. The results showed that compared to the open field cultivation，facility cultivation significantly advanced the sprouting stage of jujube floral bud，extended the duration of individual flower blooming and peak flowering periods，and increased both the quantity and sugar content of nectar. Overall，under the facility cultivation，‘Dongzao’exhibited superior in phenological phases，flower development，as well as nectar composition and quantity，compared to those under the traditional open field cultivation.

This study utilized a hybrid offspring population as its experimental material. The survival of young fruits was investigated based on conspicuous differences in fruit size between frozen-injured and surviving young fruits during the fruit enlargement period. The number of survived young fruits per plant（variable X），the average number of survived young fruits per fruit cluster（variable Y），and the percentage of survived fruit clusters（variable Z）were custom-defined and transformed into three data samples. The kurtosis，skewness，and probability density distribution functions of each sample indicated that variable Z exhibited a closer approximation to a normal distribution compared with X or Y. Following Box-Cox transformation，variables Y and Z successfully passed the Shapiro-Wilk test，confirming their adherence to a normal distribution. The optimal values for parameters used in the definitions of Y and Z were determined by introducing the variable S，which assessed the degree to which the data conformed to a normal distribution and maintained a relatively large sample size. The findings revealed that setting parameter a（the expected yield）to 4 and parameter b（the number of fruit clusters）to 12 yielded data samples of the average number of survived fruit clusters（Y）and the percentage of survived fruit clusters（Z）that most closely aligned with a normal distribution while maximizing the sample size. At this juncture，the Box-Cox transformation of the（Y）variable was deemed inconsequential，whereas the transformation of the（Z）variable coincidentally corresponded to a logarithmic transformation. The results of this study suggest that the percentage of survived fruit clusters（Z）can effectively reflect both freezing tolerance and yield，with data acquisition being simple and efficient，thus rendering it suitable for large-scale freezing tolerance evaluation in loquat hybrid offspring.

CRISPR/Cas9 is the immune defense system in bacteria and archaea. In 1987，a special repeat interval sequence was firstly discovered in Escherichia coli. Later，this repeat interval sequence was also found in more than 20 bacteria and archaea. In 2002，this special sequence was officially named as CRISPR. Subsequently，a series of studies using CRISPR/Cas9 technology for gene editing were carried out. CRISPR/Cas9 technology is the third generation gene editing technology，following ZFNs（zinc finger nucleases）technology and TALENs（transfer activator like effector nucleases）technology. This system has the advantages of simple operation design，high mutation efficiency，low cost，and has been successively applied in many horticultural plants such as citrus，grape，banana，strawberry，cucumber，and potato. This article reviews the principles and research progress of CRISPR/Cas9 technology，discusses the developmental history of various editors，including single base editor，double base editor，and guided editor，introduces the application of CRISPR/Cas9 technology in horticultural plants，and finally proposes the remaining problems and future prospects of CRISPR/Cas9 technology.

In order to explore the function of SlWRKY46 in response to low temperature stress，the CDS sequence of SlWRKY46 cloned from tomato‘Micro-Tom’leaves was analyzed. The result showed that SlWRKY46 belonged to Ⅱa group of WRKY family and encoded 253 amino acids. SlWRKY46 was localized in the nucleus by subcellular localization analysis. SlWRKY46 had no transcriptional activation activity in yeast. SlWRKY46 could form homologous dimers by yeast two-hybrid yeast（Y2H）. The results of real-time fluorescence quantitative PCR（qRT-PCR）showed that the expressions of SlWRKY46 were significantly induced by low temperature and abscisic acid（ABA）. The GUS staining of SlWRKY46 promoter transgenic tomato also cloud be induced by low temperature and ABA. The overexpressed SlWRKY46 tomato lines had higher cold tolerance compared with wild-type. The overexpressed SlWRKY46 tomato lines exhibited lower reactive oxygen species accumulation and malondialdehyde levels，and higher antioxidant enzyme activities and proline accumulation compared with wild-type under low temperature treatment. The expression levels of genes related to antioxidant enzyme and ABA showed significant differences between overexpressed SlWRKY46 tomato lines and wild-type under low temperature treatment. Taken together，these results indicated that SlWRKY46 positively regulated the cold tolerance of tomato by antioxidant enzyme and ABA pathways.

Virus-induced gene silencing（VIGS），a reverse genetic technique based on plant antiviral mechanism，has been widely used in the study of plant growth and development，signal transduction，metabolic pathways and stress resistance due to its advantages of independent of plant genetic transformation system，time-saving，easy and efficient operation，and high-throughput. In this paper，the mechanism，application and problems of VIGS were reviewed，and the vector construction strategies and influencing factors were discussed emphatically，aiming to provide reference for the further development and application of VIGS technology.

To investigate the function of MrSPL4 in response to drought and low temperature stress in Chinese bayberry，the cis-acting element of MrSPL4 promoter and treating MrSPL4-OE transgenic tobacco T₂ generation strain with drought and low temperature stress were analyzed，observing its seed germination rate and plant phenotype，and measuring plant physiological indexes to clarify the function of MrSPL4. The results showed that the promoter region of MrSPL4 contains cis-acting elements for drought induction，low temperature response，defense and stress response，and the other important cis-elements. Compared with wild-type tobacco（WT），under drought stress，MrSPL4-OE transgenic tobacco seed germination rate was significantly reduced. There was no significant difference in the reduction of plant water loss and wilting between WT and MrSPL4-OE. Except for a significant decrease in H₂O₂ content，there was no significant difference in other indicators. Transfer to normal conditions after low temperature stress，the germination rate of seeds significantly increased. Plant greening and wilting were reduced. SOD and POD enzyme activities increased significantly，while the content of MDA，H₂O₂，proline，and soluble sugar decreased significantly. The results indicated that MrSPL4 positively regulates the response process of tobacco to low temperature stress，improves its ability to tolerate low temperature，but inhibits the germination rate of tobacco seeds under drought stress.

The plant-specific NAC（NAM，ATAF1/2，CUC2）transcription factors play important roles in regulating fruit quality. To explore the role of the NAC in the regulation of soluble sugars in peach （Prunus persica）fruit quality，a total of 117 potential peach NAC members（PpNAC）were identified with an uneven distribution across all eight chromosomes as well as a scaffold. Phylogenetic analyses indicated that these PpNAC were classified into 13 subgroups. The NAC gene PpNAC050 that is highly expressed during later fruit development were further characterized，and it was in nucleus with transcriptional activation. Transient overexpression of PpNAC050 in peach fruits significantly increased fructose content and glucose content in peach fruit flesh. EMSA and dual-luciferase assays showed that PpNAC050，being a transcriptional repressor，directly bound to the promoters of PpERDL6-1（PpERDL16），a vacuolar membrane monosaccharide transporter gene regulating fructose content，suggesting that PpNAC050 positively regulated fructose accumulation by repressing PpERDL6-1 gene expression.

In order to study the response of GH3.17 gene to salt stress in strawberry，the evolutionary relationship and physicochemical properties of FaGH3.17 were analysed using bioinformatics，and the gene was cloned and subsequently subcellularly localised in tobacco and heterologously overexpressed in Arabidopsis to verify its function in salt stress. The results showed that FaGH3.17 is an acidic and unstable hydrophobic，non-secretory protein，and the analysis of the evolutionary relationship of species revealed that FaGH3.17 is the closest relative to Potentilla anserina. Subcellular localisation in tobacco revealed that FaGH3.17 was mainly localised in the nucleus and cell membrane. Heterologously overexpression analysis in Arabidopsis thaliana revealed that under salt stress，the conductivity，MDA and H₂O₂ content were higher than those of wild-type plants，which were elevated by 15.43%，42.97%，and 18.86%，respectively，whereas the Pro content，POD，SOD，and CAT activities were significantly lower than those of the wild-type plants，which were reduced by 13.28%，15.42%，14.22%，19.87%，respectively. And the relative expression of salt-responsive genes were all significantly reduced. It was shown that heterologous overexpression of FaGH3.17 significantly reduced the antioxidant enzyme activities and osmoregulatory substance contents in Arabidopsis，which predicts that GH3.17 may attenuate the salt tolerance of plants.

Discovering natural triploids from diploid seedling offspring is an effective mehod to cultivate new seedless citrus cultivar. In this study，the small plump seeds of Orah were germinated and sowed，and the ploidy of seedling offsprings was identified by morphological screening，flow cytometry and chromosome counting. A total of 98 triploid lines of Orah seedlings were obtained. Two pairs of SSR primers with polymorphism between the female parent and its candidate male parent were used to analyze the hybrid origin of triploid progenies. It was found that only the amplification product of Orah mandarin could be detected in the triploid progenies. Further genetic analysis was performed using 36 pairs of S-RNase primers. Results showed that the S genotype S₁₁/S_M of Orah mandarin was detected in all triploid progenies，and the S genotype S₂₂ of the candidate male parent Shatangju occurred in two lines，presumed that these two lines were triploid progenies produced by the hybridization of Orah and Shatangju，and were formed by fertilization of 2n female gametes. The remaining lines might be autotriploids produced by selfing of Orah. Compared with the diploid seedlings，the triploid seedlings of the same age grew slowly，the internodes became shorter，the dwarfing was obvious，the main roots were short and thick，the fibrous roots were less，the leaves were dark green and thicker. Under the same cultivation and management conditions，the expression of multiple stress response related genes（CitCOMT，CitGRAS，CitERF4 and CitERF9）in the leaves of allotriploid plants was significantly up-regulated compared with diploid and autotriploid plants.

To investigate the reason for the fruit mastication difference between citrus triploid progeny with their diploid parents，two triploid hybrids derived from the crosses with Bendizao tangerine and Red tangerine as female parent were selected as materials to investigate the effect of segmental membrane structure and its components on the mastication of triploid fruits comparing with their diploid parents. In this study，using the two diploid parents as the control，the fruit mastication of the two triploid hybrids was firstly determined with texture analyzer at mature stage. It showed that the hardness and shear force of the segmental membrane of the two triploid progenies were significantly higher than that of their diploid parents，indicating that the segmental membranes of the two triploid hybrids might thicker than that of their corresponding diploid parents. It showed that the thickness and cell layer number of the segmental membranes of the two triploid hybrids were significantly higher than that of their corresponding diploid parents at the same developmental stage started from 120 days after flowering（DAF）. The ultrastructure of the segmental membrane showed that the cell walls in the two triploid hybrids were thicker and the cellulose microfibrils were denser than those of their diploid parents. The content of water-soluble pectin，protopectin，cellulose and hemicellulose in the segment membrane of the two triploid hybrids were significantly higher than that of their diploid parents，while the lignin content was significantly lower at some developmental stage. In conclusion，segmental membrane thickness，water-soluble pectin，protopectin，cellulose and hemicellulose contents are important factors affecting the mastication of some citrus triploid hybrids，providing some useful evaluation indexes to screen superior triploid lines with good fruit mastication quickly from a large-scale triploid population.

Sunburn is a common physiological disorder in citrus production，but the underlying mechanism remains largely unknown. The study was carried out at Fenghuang Mountain，Banyue Town，Dangyang City，Hubei Province in 2021. Satsuma mandarin（Citrus unshiu Marc.）and Ponkan（C. reticulata）were used as experimental materials to investigate the difference in sunburn and potential mechanisms by examining peel injury degree，performing cytological observation，measuring antioxidant content and gene expression levels. The results showed that Satsuma mandarin was more susceptible to sunburn than Ponkan. Significant difference in the incidence rates of sunburn was observed between the two varieties，43.12% for Satsuma mandarin and 22.52% for Ponkan. Sunburn seriously influenced the compactness of pericarp cells and resulted in the accumulation of lignin. Satsuma mandarin fruits were found to accumulate greater level of reactive oxygen species（ROS）. In addition，nobiletin，a critical metabolite in the polymethoxyflavone metabolic pathway，was significantly enriched in Ponkan fruit peel. Consistently，transcript levels of CrCHS2，CrCHI and CrFNS，encoding crucial enzymes involved in biosynthesis of flavonoid，and CrOMT2 in the polymethoxyflavone pathway were significantly induced in the sunburnned Ponkan fruit peel. Taken together，these findings indicate that the main reason for the difference in sunburn between Satsuma mandarin and Ponkan is that the latter contains more antioxidant that can effectively decrease the ROS accumulation，thus leading to mitigation of sunburn-derived damage.

This review comprehensively examined the impact of temperature on anthocyanin accumulation by regulating the expression of genes related to anthocyanin synthesis，degradation，and transport. Temperature can also modulate anthocyanin synthesis through epigenetic and protein modifications，including DNA methylation，protein ubiquitination，protein SUMOylation，and protein phosphorylation levels. Furthermore，temperature synergistically interacts with light and hormones to regulate anthocyanin accumulation. This article provided a theoretical reference for the in-depth analysis of the effects of temperature on anthocyanin accumulation in plants and offers prospects for future research directions.

In this study，the BoBRC1 gene was cloned from the elite broccoli inbred line L461. Expression pattern analysis showed that BoBRC1 had the highest expression level in axillary bud tissues，and changed dynamically with axillary bud growth. According to the sequence of BoBRC1，two targets were designed on the first exon，and a CRISPR/Cas9 gene editing vector was constructed. The construct was introduced into L461 by Agrobacterium-mediated genetic transformation，and a total of 18 plants were confirmed as positive transgenic. The results showed that three plants harbored mutations in at least one of the targeted regions corresponding to an editing efficiency of 16%. Among them L461-3 was edited in both Target 1 and Target 2 while L461-1 and L461-11 were edited in Target 2. Compared with the wild type，the homologous editing mutants showed a significant increase in the number and length of lateral branches. In the bobrc1 mutant，qRT-PCR analysis of key genes downstream of lateral branch gene BoBRC1 showed a significant decrease in the expression of the BoHB21，BoHB53 and BoNCED3 genes while the expression of the BoHB40 significantly increased. This study verified the function of BoBRC1 gene in the regulation of lateral branch development in broccoli，and knocking out can promote the growth of broccoli lateral branches.

In order to study the effect of GRF/GIF family genes on the efficiency of genetic transformation and regeneration，10 VvGRF and 4 VvGIF genes were identified in grape genome. VvGRF contains family conserved domains WRC and QLQ，VvGIF contains conserved domains SNH and QG. The regeneration of tobacco overexpressing VvGRF and VvGIF after one month of cultivation was significantly better than that the empty control. VvGRF8-GIF2 and VvGRF4-GIF2 are overexpressed in tobacco，and the regeneration efficiency is as high as 73.58% and 65.05%，which is 2.4-2.7 times that of control. Overexpression of rVvGRF8-GIF2（VvGRF8-GIF2 after mutation of miR396 binding target site）showed the best regeneration efficiency，reaching 83.43%，which was 3.1 times that of control. Compared with the overexpression transformation of VvGRF8-GIF2 chimera，the promotion effect of constructed VvGRF8，VvGIF2 homologous chimera VvGRF4-GIF2，VvGRF5-GIF2 and VvGRF8-GIF3 after overexpression is relatively weak. According to the experimental results，VvGRF8 and VvGIF2 can improve the regeneration efficiency of plant genetic transformation.

Apple chlorotic leaf spot virus（ACLSV）possesses a positive single stranded RNA and widely infects pear and other fruit trees. The coat protein（CP）of the virus functions in the viral pathogenesis. In order to gain a deep understanding of the interaction characteristics between the virus and its host plants，a yeast two hybrid（Y2H）assay was carried out by using pGBKT7-CP（expressing ACLSV CP）as a bait vector to screen pear proteins in a cDNA library of pear‘Hongxiangsu’，and 33 host factors potentially interacting with ACLSV CP were identified. Furthermore，the interaction relationships between CP and two RING type E3 ubiquitin ligases（named MIEL and BOI）from pear were confirmed by both Y2H and bimolecular fluorescence complementation（BiFC）assays. In BiFC assays，the interaction signal of CP with BOI located at plasmodesma and nucleus，which was similar to the subcellular locations of the two proteins. The interaction signal of CP with MIEL located at endoplasmic reticulum and nucleus，which was similar to the subcellular locations of MIEL. The truncated mutants of the three proteins were constructed. In Y2H assays，only MIEL mutant containing the zf CHY domain（1-99 aa）interacted with CP，and other MIEL mutants and all BOI mutants failed to interact with CP，and all CP mutants cannot interact with the two host proteins.

The bud sport mainly result from genetic changes in bud meristem cells，which often occurs on tree fruit，most bud sports are inferior mutants for cultivation，and a few become elite cultivar. Present studies on bud sport generally start with morphological and physiological investigation，and then combine molecular methods to elucidate the mechanism. The methods to detect the presence of mutations mainly include DNA markers such as SSRs and other molecular marker，transposon InDel detection，InDel mutation detection，DNA methylation detection，high-throughput sequencing detection，MITEs sequence detection，etc. Both similarities and differences are detected in various types of bud sports among tree species. By summarizing the color，ripening stage，canopy shape，tree vigor，and other horticultural characteristics of fruit trees，the possible mechanism of bud sport was analyzed. This paper can provide a reference for analyzing the molecular mechanism of bud sport in tree fruits and subsequent marker-assisted breeding.

The seedlessness cause of‘Gongshui Baiyou’pummelo was investigated through morphological and cytological observations. The results showed that both the female and male gametophytes of‘Gongshui Baiyou’developed normally and were fertile. After self-pollination，pollen tube growth stopped at 1/3 of the stigma，showing incompatibility. The fruit setting rates of unpollinated flowers after 7，14，21 and 49 days were 60%，32%，14% and 9%，respectively，and they could develop into seedless fruits，which indicated that they had parthenocarpic ability. Additionally，the sectioning of ovule tissue development in the early stage showed that the embryo sac tissue of seedless‘Gongshui Baiyou’began to shrink 21 days after emasculation. Its cross with‘Shatianyou’and‘Gongshui Baiyou’pummelos showed affinity and could contain full and normal seeds. In conlution，both self-incompatibility and parthenocarpy are the main reasons for the formation of seedless fruit of‘Gongshui Baiyou’.