This study aims to explore recent advances and challenges in developing citrus germplasm resistant to the Asian citrus psyllid (ACP) using CRISPR/Cas9 gene editing technology.The focus is on identifying key genetic targets, evaluating the effectiveness of CRISPR/Cas9-mediated edits, and discussing the implications for sustainable citrus production.Several case studies demonstrate the potential of CRISPR/Cas9 to enhance resistance without compromising yield and fruit quality.Advances in CRISPR/Cas9 techniques, such as base and prime editing, have improved the precision and efficiency of gene editing in citrus.Additionally, field trials have validated the effectiveness of these edited plants in real-world conditions.The findings underscore the significant potential of CRISPR/Cas9 technology in developing ACP-resistant citrus germplasm.However, technical challenges, off-target effects, genetic stability, and regulatory and public acceptance issues remain.Continued research, interdisciplinary collaboration, and clear regulatory frameworks are essential to fully realize the benefits of CRISPR/Cas9 in citrus breeding.These efforts are crucial for ensuring the long-term sustainability and resilience of the citrus industry.

Background Citrus reticulata Blanco ‘Orah’ is one of the most widely grown citrus varieties in southern China. It has been proven that microbial fertilizer and organic manure combined fertilization could improve the yields and appearances of ‘Orah’ fruits. However, details regarding the mechanisms underlying the effects of combined fertilization on the agronomic traits and rhizosphere bacterial community of plants still need to be elucidated. Results This study compared the rhizosphere bacterial community and carotenoids of ‘Orah’ with (WYT group) and without (WYCK group) combined fertilization. The WYT group was sprayed with 50 ml Strongreen and 250 g of Yumeiren five times while WYCK group did not sprayed. Combined fertilization increased fruit weight and the Citrus color index (CCI) significantly (P < 0.05). By 16s rRNA sequencing, 7,126 operational taxonomic units (OTU) were obtained. A higher Shannon index was observed in the WYT group compared to that in the WYCK group. Comparison between the two groups showed that Pseudomonas was enriched in the WTY group, and Cyanobacteria was enriched in the WYCK group. At the family level, Phyllobacteriaceae was significantly abundant in the WTY group, whereas Thermosporothrix and Sphingobium were significantly abundant in the WYCK group. A total of 51 carotenoid components were tested using UPLC-MS/MS. In the pulp tissues, 37 carotenoid components were decreased in the WTY group compared to those in the WYCK group. In fruit skin, 24 significantly different components (7 downregulated and 17 upregulated) were identified in WTY compared to those in WYCK. Correlation analysis revealed that the network between OTUs and carotenoids contained seven carotenoid components and four OTUs. Four OTUs, strain TRA3-20 (a eubacterium), Roseiflexus, OPB35, and Fictibacillus contributed to carotenoid accumulation regulation in fruit skin. Conclusions By exploring the complex interactions between soil microbiota and fruit traits, our research has illuminated potential pathways through which these microbial communities influence the biosynthesis and accumulation of carotenoids. In conclusion, this study provides valuable information regarding soil bacterial communities related to carotenoid accumulation in ‘Orah’.

Citrus reticulata Blanco 'Orah' is grown throughout southern China and provides enormous economic value. However, the agricultural industry has suffered substantial losses during recent years due to marbled fruit disease. The present study focuses on the soil bacterial communities associated with marbled fruit in 'Orah'. The agronomic traits and microbiomes of plants with normal and marbled fruit from three different orchards were compared. No significant differences were found in agronomic traits between the groups, except for higher fruit yields and higher quality of fruits in normal fruit group. Additionally, a total of 2,106,050 16S rRNA gene sequences were generated via the NovoSeq 6000. The alpha diversity index (including the Shannon and Simpson indices), Bray-Curtis similarity, and principal component analyses indicated no significant differences in microbiome diversity between normal and marbled fruit groups. For the healthy 'Orah', the most abundant associated phyla were Bacteroidetes, Firmicutes, and Proteobacteria. In comparison, Burkholderiaceae and Acidobacteria were the most abundant taxa with the marbled fruit group. In addition, the family Xanthomonadaceae and the genus Candidatus Nitrosotalea were prevalent with this group. Analysis using the Kyoto Encyclopedia of Genes and Genomes pathways showed that several pathways related to metabolism significantly differed between the groups. Thus, the present study provides valuable information regarding soil bacterial communities associated with marbled fruit in 'Orah'.

为了评价'探戈'在德保县的初步表现,2017年7月海升集团从重庆晚来甜苗木有限公司购入'探戈'柑橘苗木,种植于广西壮族自治区百色市德保县龙光乡巴考村.通过2019～2021年连续3 a对其物候期、病虫害发生情况观察以及果实品质分析.结果表明,'探戈'在百色德保地区于12月下旬成熟,果肉为深橘色,平均单果重146.38 g,可食率78.05％,可溶性固形物含量11.97％,柠檬酸含量0.39％,平均每100 mL果汁维生素C含量16.21 mg,总糖含量11.46％;该品种有较好的适应性、抗病性,耐储运,产量中等,可在适宜'W·默科特'种植的地区适量发展,尚不宜大面积推广.

[目的]探究枳橙砧木对沃柑树体及果实品质的影响,为筛选桂南地区沃柑适宜的砧木提供理论依据.[方法]在广西南宁市武鸣区采取长期定位试验,对嫁接在枳橙上的沃柑果实品质进行持续3年(2018—2020年)的研究,以资阳香橙砧、枳砧和红橘砧沃柑为对照,分析其树体指标(砧木干周、接穗干周、干周差、株高、挂果数量)及果实品质指标(单果重、果实横径、纵径、果形指数、果皮厚度、可食率、维生素C、可溶性固形物、柠檬酸、总糖、固酸比)等的变化.[结果]综合3年数据可知,枳橙砧沃柑在单果重、挂果数量和部分品质指标上优于其他砧木,3年平均挂果数为299个,单果重为143.07 g,维生素C含量为19.92 mg/100 mL,可溶性固形物含量为12.51％,柠檬酸含量为0.584％,总糖含量为12.46％,固酸比为21.42.枳橙砧与枳砧相比,呈现出生长势强,挂果数量多等优势,但与香橙砧相比,差异不显著(P>0.05,下同);结合单果重表现,枳橙砧沃柑无明显的下降趋势,与香橙砧沃柑相比,均能持续稳产.枳橙砧沃柑的果实品质整体表现低于枳砧沃柑,但进入丰产期后,二者品质差异不显著.对比其他3种砧木,红橘砧沃柑整体表现较差,主要为挂果数量较少,果实品质指标不理想,其中3年平均挂果数量为185个.[结论]枳橙砧沃柑在桂南地区综合表现较好,可考虑枳橙砧作为桂南地区沃柑的适宜砧木;但枳橙砧不适宜在缺锌较严重的地块种植,且在生产中,枳橙砧应控制树势,适时修剪,不适宜密植.

Citrus fruits exhibit vivid color and are favored extensively. However, the biochemical and molecular mechanism of Citrus Reticulata Blanco fruits coloring, especially the effect of transplantation on fruits coloring, is unclear. Herein, RNA-Seq and carotenoids profiling were applied to investigate the effect of transplantation on Orah mandarin fruits coloring. Transplantation induces fruit color shallowing, Ca2+ and ACC level declining and IAA level increasing. Transplantation induced variation in fruit skin and pulp carotenoids, mainly β-citraurin as one of the important pigments of citrus peel. 2253 up-regulated genes, 1103 down-regulated genes in skin and 815 up-regulated genes, 534 down-regulated genes in pulp of transplanted tree fruits were identified by RNA-Seq. The DEGs involved hormone signal, carotenoids biosynthesis and TFs such as MYB and bHLH family TFs. The carotenoid cleavage dioxygenase gene (Ciclev10028113m.g) is positively correlated with β-citraurin and regulated directly and/or indirectly by MYB1R1, PIF4, ACC and IAA. Integrative analyses revealed potential molecular insights into Orah mandarin peel color variation during transplantation.

在桂中南柑橘园区武鸣区、德保县、西乡塘区、来宾市、隆安县、马山县、上林县、钟山县等8个市(县、区)选取104个具代表性的柑橘园采集土壤样本,定量测定土壤pH、有机质和矿质元素含量等,并进行主成分和聚类系统分析,以探明桂中南柑橘园区土壤养分丰缺状况.结果表明:桂中南柑橘园土壤pH值以酸性为主,最适宜柑橘生长的微酸性土壤(5.5≤pH<6.5)占比仅为19.2％;49.0％的橘园土壤有机质含量不足;土壤碱解氮及有效镁、有效锌、有效铜、有效硼含量普遍不足,低于适量水平的比例分别为51.0％、93.3％、93.3％、89.4％、92.3％,特别是镁和锌缺失严重,缺失水平占比分别为59.6％和63.5％;有效磷和有效钙主要处于适宜水平,适量以上水平的占比分别为76.0％和71.2％;土壤有效钾丰缺并存,不足、适宜、超标的比例分别为42.3％、24.0％、33.7％;有效铁、有效锰含量丰富,处于适量以上水平的比例分别为83.7％和89.4％;主成分和聚类分析表明,德保县、钟山县和武鸣区果园的土壤养分综合状况要好于其他市(县、区).可见,桂中南柑橘产区生产上应当注意调节土壤pH,适当补充氮、镁和锌肥及增施有机肥,减少铜制剂用量,控制土施硼肥,并重视磷、钙和钾肥的补充与平衡.

对11个柑橘品种离体叶片进行溃疡病菌接种,统计病情指数;选取5个对溃疡病易感的柑橘品种在病菌接种后不同时期进行药剂处理试验,评价溃疡病病菌接种后防治的最佳时期和药剂防效.结果表明,接种12 d溃疡病抗性由高到低依次是长安金柑>贡柑>红肉蜜柚>砂糖橘>金橘蜜柚>马家柚>沙田柚>橘红>纽荷尔脐橙>沃柑>茂谷柑;4种药剂防效由高到低依次为可杀得>中生菌素>代森锰锌>乙蒜素,病菌接种后12 h内进行药剂处理,防效较高,超过24 h防效下降趋势增大.

为了探明"沙糖桔"芽变早熟品种"金葵蜜桔"在广西的栽培表现,2015年从广州引进枳砧"金葵蜜桔"到南宁市武鸣区种植,以枳砧"沙糖桔"为对照,2019-2020年连续2年对其植物学性状、物候期、果实品质等进行观测,并总结其栽培技术.结果 显示,"金葵蜜桔"树势中庸,果实成熟期在11月中下旬,果形指数0.82,高扁圆形,平均单果质量44.92 g,单株产量27.1 kg,可食率为78.7％,可溶性固形物13.9％,总糖12.1 g/100g,可滴定酸0.39 g/100 mL,固酸比36.22,维生素C 30.33mg/100 g.该品种果实外观漂亮、无核、化渣、蜜甜、硬度较高,较"沙糖桔"提早15～20 d成熟.该品种适宜于在广西适度发展,生产上注意保花保果和防裂果.

为研究易粒化柚和不易粒化柚贮藏期间的生理生化差异,以易粒化品种三红蜜柚、红肉蜜柚和不易粒化桂红柚1号的果实为试验材料,采后贮藏于温度18℃、空气相对湿度50％的贮藏室,于贮藏0、20、40、80和120 d时取样测定了粒化指数、失重率、果肉出汁率、抗坏血酸(ASA)、可溶性固形物和可滴定酸.结果 表明,桂红柚1号在采收时和贮藏期均无粒、化;三红蜜柚和红肉蜜柚在采收时粒化指数分别为9.9％和7.15％,贮藏期粒化程度呈加重趋势,贮藏120 d时粒化指数分别达31.34％和24.81％.与三红蜜柚和红肉蜜柚相比,桂红柚1号呈现果肉出汁率高,ASA、可滴定酸含量高和可溶性固形物降低时间较晚的生理生化特点.桂红柚1号可作为培育不易粒化品种的育种材料.

2019年从容县各乡镇轻度感病、中度感病、重度感病以及未感病但有其他黄化症状的305株沙田柚树上,采集了590份不同症状的叶片样品,在Nested-PCR检测的基础上,使用广州讯动网络有限公司开发的手持式近红外光谱仪采集光谱,建立标准数据库模型并进行验证.结果 表明,以11月307份样品建立的近红外光谱标准数据库模型的检测效果较佳,总识别率81.75％,黄龙病阳性样品和阴性样品的识别率分别为83.41％和78.80％,假阳性率7.62％,假阴性率10.62％.其中,对斑驳黄化叶样品(Nested-PCR检测100％阳性)的识别率最高,达96.72％.在对2月283份样品的验证中,该模型识别能力较差.与Nested-PCR检测相比,近红外光谱检测具有无损、快速的优点,但在对带菌的无症状叶、缺索黄化叶(主要为缺镁)和不带菌的均匀黄化叶和其他黄化叶(主要为烂根、损伤导致的黄化叶)等的检测中灵敏度较低,分别易发生漏检和错检.

为筛选出防治柑橘木虱的有效药剂,选用7种杀虫剂进行室内毒力测定和田间药效试验.室内毒力测定结果表明,处理72 h时,22.4％螺虫乙酯悬浮剂、20％双甲脒乳油、25％噻虫嗪悬浮剂、5％啶虫脒乳油、4.5％联苯菊酯水乳剂、25％喹硫磷乳油、25％乙基多杀菌素水分散粒剂的LR50分别为21.394、13.895、10.205、29.588、16.912、19.044、11.425 g a.i./hm2.田间药效试验结果表明,22.4％螺虫乙酯悬浮剂、5％啶虫脒乳油、25％喹硫磷乳油药后14 d时最高校正防效分别为52.69％±4.64％、55.77％±13.10％、71.09％±4.06％;20％双甲脒乳油1000、2000倍液,25％噻虫嗪悬浮剂1000、2000、4000倍液,4.5％联苯菊酯水乳剂1000倍液及25％乙基多杀菌素水分散粒剂4000、2000、1000 mg/kg水的使用剂量下对柑橘木虱的校正防效超过80％,其中20％双甲脒乳油、25％噻虫嗪悬浮剂、25％乙基多杀菌素水分散粒剂速效性及持效性均较好.在广西地区柑橘木虱的防治中,可推广使用25％噻虫嗪悬浮剂1000～4000倍液,20％双甲脒乳油1000～2000倍液,25％乙基多杀菌素水分散粒剂1000～4000 mg/kg水,4.5％联苯菊酯水乳剂1000倍液.

为增加"桂葡柚1号"果实的商品性,在广西玉林和南宁"桂葡柚1号"生产基地选用不同纸袋(白色单层纸袋、外黄内黑单层纸袋、外黄内黑双层纸袋、外红内黑双层纸袋)进行了套袋试验.结果 表明,套袋能明显提升果实色泽,其中,外红内黑双层纸袋和外黄内黑双层纸袋套袋果实的色泽饱和度高,转色均匀,效果好;套外红内黑双层纸袋的果实可溶性固形物、总糖、维生素C下降较小,可滴定酸下降较大,固酸比高于对照,风味较好,果皮增厚不明显,硬度显著增加,有利于贮藏运输,最适宜"桂葡柚1号"生产;不同年份的天气不同,导致套袋内小环境和大环境差异大小不同,对果实品质的影响程度也不同.

以茂谷柑果实为供试材料,采收后分别用清水、200 mg/kg 2,4-二氯苯氧乙酸(2,4-D)+250 mg/kg咪鲜胺溶液、1.5％壳寡糖溶液处理,晾干贮藏于6℃环境中,研究茂谷柑果实低温贮藏期间品质变化情况.结果表明,贮藏60 d内,茂谷柑可溶性固形物含量总体升高,可滴定酸含量下降,维生素C含量先升高而后下降至较低水平.各处理果实贮藏期间各项指标对比,2,4-二氯苯氧乙酸+咪鲜胺处理总体稍好于壳寡糖处理,2种药剂处理均优于对照.

桂妃是以自交系HL4334为母本,以自交系HHH3-1为父本配制而成的早熟西瓜一代杂种.春季栽培全生育期96 d(天)左右,果实发育期30 d(天)左右;秋季栽培全生育期75 d(天)左右,果实发育期28 d(天)左右.植株生长势强,易坐果,果实椭圆形,果皮深绿色覆墨绿色条带,皮厚0.8～1.0 cm,果肉大红色,肉质细腻甜脆,中心可溶性固形物含量11.5％,单果质量2.5～3.8 kg,每667 m2产量2300 kg左右,适宜广西地区露地栽培.

柚类在幼果期通常需要进行疏果处理,为提高柚类幼果的利用率,测定6种不同柚类幼果总黄酮含量及柚皮苷含量,以橘红为对照,筛选不同柚类品种作为总黄酮及柚皮苷提取原料的可行性.结果表明:4个琯溪蜜柚类品种及马家柚幼果的总黄酮类及柚皮苷含量均高于橘红,均可考虑其幼果作为提取总黄酮及柚皮苷的原料,使柚类幼果资源得到合理有效利用;从试验品种提取的稳定性出发,柚皮苷的提取可优先考虑金橘蜜柚、总黄酮的提取可优先考虑三红蜜柚.

近年来我国南部柑桔产区为应对柑桔黄龙病威胁,开始探索和推行防虫网棚栽培.为了解网室栽培对晚熟柑桔生长及病虫害发生情况的影响,在桂南地区对枳砧沃柑、茂谷柑开展网室与露地栽培对比试验.结果表明,与露天栽培相比,网室栽培条件下晚熟柑桔的萌芽、开花和生理落果物候期提早,但果实转色期和成熟期推迟,沃柑总糖含量显著降低,茂谷柑维生素C含量显著提高,其他品质指标无显著变化;在同等管理条件下,网室栽培能有效预防柑桔溃疡病及黄龙病的发生,但红蜘蛛和煤烟病发生的概率增大.

为筛选出适合广西茂谷柑的砧木,以南宁市武鸣县一个果园2007年和2010年定植的枳、酸桔、柠檬和红桔砧茂谷柑为试材,2015-2017年连续3年对树体生长情况、产量、果实品质和抗病性等进行了比较分析.结果 表明,4种砧木与茂谷柑的亲和性无明显差异,均表现亲和力强.枳砧茂谷柑果实可溶性固形物高于其他砧茂谷柑,果面橙红,果皮薄而光滑,外观品质优,树冠紧凑矮化,早结性最好,但易感裂皮病,中后期产量较低,早衰现象严重.酸桔砧和红桔砧茂谷柑的果实品质居中,树体相对易感脚腐病,酸桔砧茂谷柑早结性差,红桔砧茂谷柑早结性居中,两者投产中后期均表现为稳定丰产;柠檬砧茂谷柑果实皮较厚,可溶性固形物偏低,品质相对较差.枳、酸桔和红桔是茂谷柑的优良砧木.

[目的]探究沃柑感染黄龙病的田间症状表现及各症状与感染黄龙病的相关性,为种植者尽早鉴别黄龙病树和及时做好黄龙病防控工作提供参考依据.[方法]从广西不同地区沃柑果园采集沃柑黄龙病疑似样品,对样品按症状分类并记录,用试剂盒法提取叶脉和果柱基因组DNA,采用黄龙病亚洲种的16S rDNA特异引物fD1/fD2和OI1/OI2进行巢式PCR(Nested-PCR)扩增,扩增结果在1％琼脂糖凝胶电泳上检测,统计不同症状样品的阳性率.[结果]收集的214份黄龙病疑似样品中,不同症状样品均检出黄龙病亚洲种病原菌,检出阳性率表现为典型红鼻子果=斑驳黄化叶>果蒂稍红果>均匀黄化叶>叶脉黄化叶>僵果>缺锌黄化叶>其他黄化叶>正常叶.各症状类型与感染黄龙病均存在相关性,但存在差异,其中,典型红鼻子果和斑驳黄化叶阳性率均为100.0％,与感染黄龙病相关性最大;其次果蒂稍红果阳性率为90.9％,与感染黄龙病相关性很大;夏、秋梢均匀黄化叶阳性率为46.5％,与感染黄龙病相关性大.沃柑感染黄龙病后症状复杂,大多出现两种以上复合症状,结果树最初症状为出现果蒂稍红果,落果较多,未结果树以夏、秋梢黄化居多,根系容易受损;正常叶阳性率达16.7％,说明沃柑感染黄龙病早期不易显症.[结论]沃柑出现典型红鼻子果和斑驳黄化叶,可田间诊断为黄龙病树;出现果蒂稍红果,并严重落果,基本可田间诊断为黄龙病树;夏、秋梢均匀黄化黄龙病检出率高,但确诊还需与其他疑似症状(叶脉黄化叶、僵果、缺锌黄化叶、其他黄化叶和正常叶)一样通过PCR进一步检测.Nested-PCR检测技术灵敏性高,可作为沃柑感染黄龙病的早期鉴定技术.

091无核沃柑引种至广西南宁,树势生长旺盛.枳砧嫁接苗定植3年后的株高为294.40 cm,冠径为283.08 cm×265.24 cm;枳橙砧嫁接苗定植3年后株高可达335.40 cm,冠径为326.84 cm×310.82 cm.091无核沃柑果实大小适中,果实品质好,商品性高.枳砧091无核沃柑平均单果质量为160.25 g,可溶性固形物含量为13.08％;枳橙砧091无核沃柑平均单果质量为168.88 g,可溶性固形物达13.68％.091无核沃柑现蕾期在2月上旬至3月上旬,开花期在3月上旬至3月下旬,翌年1月中下旬果皮呈橙色或橙红色,开始进入成熟期,翌年2-3月品质最佳,其他物候期与普通沃柑相当.越冬落果极少,柑桔溃疡病、日灼、红蜘蛛、潜叶蛾和蓟马等常见病虫害均有发生,但不严重,主要存在部分小果和部分粗皮果等问题.总体评价,091无核沃柑在南宁栽培果实品质优秀,口感佳,值得试种,但栽培上要注意保花保果.