Salt-induced inhibition of tillering constrains rice plant architecture and yield potential. To clarify the molecular links between salt tolerance and tiller development, we compared physiological responses and tiller-bud transcriptomes of the salt-tolerant japonica cultivar Nipponbare (NIP) and the salt-susceptible cultivar Kongyu 131 (KY131) under salt stress. Time-resolved RNA sequencing revealed cultivar-specific transcriptional dynamics, suggesting that rapid acclimation and transcriptome stabilisation in tiller buds contribute to salt tolerance. Functional enrichment highlighted redox regulation, phenylpropanoid metabolism, chlorophyll biosynthesis, nitrogen metabolism, and phytohormone signalling as key processes coordinating salt adaptation and tiller-bud development. Co-expression analysis identified the NAC transcription factor OsNAC4 as a central regulatory hub. Functional analyses showed that OsNAC4 negatively regulates rice salt tolerance and tillering. Loss-of-function Osnac4 mutants exhibited enhanced salt tolerance, reduced ROS accumulation and membrane damage, increased antioxidant enzyme activities, and higher tiller number. Further analysis indicated that OsNAC4 functions as a transcriptional activator of stress-, redox-, metabolic-, and ABA-associated pathways, with OsNCED5 implicated as a downstream target mediating salt-induced ABA accumulation. Through integrated transcriptomic, physiological, and genetic evidence from comparative analyses, this study establishes a molecular connection between salt adaptation and rice tiller development and identifies candidate targets for breeding salt-tolerant rice with improved architecture.

The consequences of stacking multiple insect-resistance and herbicide-tolerance genes, particularly across the entire plant life cycle, remain inadequately understood. This study investigated the impact of stacked-trait transgenic soybeans on rhizosphere microbial communities across five growth stages (pre-sowing, V3, R3, R5, R8). Using 16S rRNA and ITS sequencing, we compared the rhizosphere microbiome of the transgenic modified soybean (GMO) with its non-transgenic control check (CK). Results showed transient but significant shifts in soil properties (e.g., available nitrogen) and microbial beta diversity during the V3 stages. However, plant developmental stage was the predominant factor shaping microbial succession, with its effect outweighing that of the transgene. No persistent changes in microbial alpha diversity were observed. We conclude that the influence of this stacked-trait soybean on the rhizosphere is growth-stage-specific and represents a minor, recoverable perturbation rather than a sustained ecological impact. These findings contribute to the ecological safety assessment of multi-gene transgenic crops.

The C3HC4-type RING finger (Ring-HC) gene family encodes zinc finger proteins crucial for plant growth and stress resistance. However, a comprehensive study on C3HC4-type RING finger genes in cotton has not been conducted to date. We identified 56 C3HC4-type RING finger genes in G. hirsutum, classified into three subfamilies with conserved structures. Evolutionary analysis indicated that this gene family has undergone strong purifying selection. Expression profiling revealed distinct tissue specificity, with significant enrichment in roots and ovules, indicating potential roles in development. Under abiotic stress, GhRHC genes showed broad responsiveness, particularly to cold. Notably, members like GhRHC1 and GhRHC34 exhibited antagonistic expression patterns: upregulation during pathogen/pest attacks but downregulation during beneficial rhizobacterial colonization. qRT-PCR analysis further confirmed the cold-induced expression of GhRHC1 and GhRHC34. Subcellular localization results preliminarily indicated that GhRHC1 and GhRHC34 proteins are localized to the nucleus and the cytoplasm. Our findings suggest that the GhRHC family plays multifaceted roles in cotton development and stress adaptation. The differential regulation of specific members suggests a possible association between differential stress-responsive regulation and the balance between defense-related responses and beneficial rhizobacterial interactions.

To evaluate the comprehensive ecological risks associated with transgenic plant residues, this study examined their impact on Eisenia fetida and their endogenous microorganisms. The results indicated that transgenic plant residues did not influence the survival or weight of E. fetida, but they significantly altered the microbial community structure at specific time points. Specifically, the diversity and structure of the fungal community exhibited significant changes on the 14th and 28th days after treatment. In contrast, the bacterial response was delayed, with 22 biomarkers, including Caproiciproducens, Lachnoclostridium, and Enterococcus, being specifically enriched on the 21st day. This study confirmed that transgenic plant residues can temporally reshape the microecology within E. fetida. The practical significance of this research lies in highlighting the importance of incorporating the microbiome into safety assessment frameworks, thereby providing a scientific foundation for developing more forward-looking ecological risk assessment standards.

With the development of commercialized planting of genetically modified crops, their ecological security risks remain a key topic of public concern. Insect-resistant genetically modified maize, Ruifeng125, which expresses a fusion Bt protein (Cry1Ab-Cry2Aj), has obtained the application safety certificate issued by the Chinese government. To determine the effects of Ruifeng125 on the diversity and dynamics of bacterial communities, the accumulation and degradation pattern of the fusion Bt protein in the rhizosphere soil of transgenic maize were detected. Results showed that the contents of Bt protein varied significantly at different developmental stages, but after straw was returned to the field, over 97% of Bt proteins were degraded quickly at the early stages (≤10 d) and then they were degraded at a relatively slow rate. In addition, the variations in bacterial community diversity in the rhizosphere soil were detected by 16S ribosomal RNA (Rrna) high-throughput sequencing technology. A total of 44 phyla, 435 families, and 842 genera were obtained by 16S rRNA sequencing, among which Proteobacteria, Actinobacia, Acidobacter Acidobacterium, and Chloroflexi were the dominant taxa. At the same developmental stage, no significant differences in soil bacterial diversity were detected between Ruifeng125 and its non-transgenic control variety. Further analysis revealed that developmental stage, rather than the transgenic event, made the greatest contribution to the changes in soil microbial diversity. This research provides important information for evaluating the impacts of Bt crops on the soil microbiome and establishes a theoretical foundation for their environmental safety assessment.

2022年,在山东省滨州市无棣县、滨城区实施了棉花病虫害绿色高效防控技术协同示范推广项目,结合棉花轻简化栽培技术,开展了棉花病虫草害生态调控、生物防治、理化诱控、科学用药等试验示范,取得了较好的效果.项目示范区比非示范区减少用药3次以上,减少农药使用量24.04％,示范区平均每亩增加纯收入100.16元,棉花产量和品质显著提高,棉田生态明显改善,棉农种植效益提高,社会、经济、生态效益显著.

Artificial modification of Bacillus thuringiensis (Bt) proteins can effectively improve their resistance to target pests, but the effect of such modification on the diversity of rhizosphere microorganisms remains unclear. Transgenic maize 2A-7 contains two artificially modified Bt proteins, mCry1Ab and mCry2Ab. These proteins can enter soil and pose a potential threat to soil microbial diversity. To assess their impacts on rhizosphere bacteria communities, the contents of the two Bt proteins and changes in bacterial community diversity in the rhizosphere soils of transgenic maize 2A-7 and its control variety were analyzed at different growth stages in 2020. The results showed that the two Bt proteins were detected at low levels in the rhizosphere soils of 2A-7 plants. No significant differences in soil bacterial diversity were detected between 2A-7 and its control variety at any of the growth stages. Bioinformatics analysis indicated that the growth stage, rather than the cultivar, was the main factor causing changes in bacterial communities. This research provides valuable data for understanding the impact of Bt crops on the soil microbiome, and establishes a theoretical basis for evaluation of their safety.

The B-box (BBX) family of proteins consists of zinc-finger transcription factors with one or two highly conserved B-box motifs at their N-termini. BBX proteins play crucial roles in various aspects of plant growth and development, including seedling photomorphogenesis, shade avoidance, flowering time, and biotic and abiotic stress responses. Previous studies have identified many different BBXs from several plant species, although the BBX family members in maize are largely unknown. Genome-wide identification and comprehensive analysis of maize BBX (ZmBBX) expression and interaction networks would therefore provide valuable information for understanding their functions. In this study, 36 maize BBXs in three major clades were identified. The ZmBBXs within a given clade were found to share similar domains, motifs, and genomic structures. Gene duplication analyses revealed that the expansion of BBX proteins in maize has mainly occurred by segmental duplication. The expression levels of ZmBBXs were analyzed in various organs and tissues, and under different abiotic stress conditions. Protein–protein interaction networks of ZmBBXs were established using bioinformatic tools and verified by bimolecular fluorescence complementation (BiFC) assays. Our findings can facilitate a greater understanding of the complexity of the ZmBBX family and provide novel clues for unravelling ZmBBX protein functions.

Transgenic maize 2A-7 expressing mCry1Ab and mCry2Ab has excellent resistance to lepidopteran pests. Previous studies have investigated the effects of several Bacillus thuringiensis (Bt) proteins on the soil. However, the effects of artificially modified Bt proteins on soil ecosystems are still unclear. To evaluate the effects of transgenic maize 2A-7 on soil, the physicochemical properties, enzyme activities and functional diversities of the microbial communities in rhizosphere soils from 2A-7 and its near-isogenic non-transgenic control Dongdan 6531 were analyzed at different developmental stages under field conditions. The alteration of six physicochemical properties (pH, total nitrogen, total phosphorus, organic matter, available phosphorus and alkali-hydrolyzed nitrogen) and six functional enzymes (catalase, alkaline phosphatase, sucrase, acid phosphatase, urease and alkaline protease) activities in the rhizosphere soils between the two maize cultivars were drastically correlated with plant growth stage, but not affected by the artificially modified Bt transgenes. An analysis of time-course Biolog data revealed that the functional diversity of microbial communities in the rhizosphere soil of 2A-7 and its control were similar at each developmental stage. The results suggest that transgenic maize 2A-7 has no significant impact on the soil ecosystem and provide valuable information on scientific safety assessments of 2A-7 and its commercial applications.

以番茄黄化曲叶病毒(tomato yellow leaf curl virus,TYLCV)及番茄褪绿病毒(tomato chlorosis virus,ToCV)为对象,用分子检测方法对山东、安徽2省病原进行鉴定.选取山东、安徽2省7个地区,对2种病毒病进行田间调查,采集疑似样品扩增序列,对其进行同源性比对和遗传进化树等分析,进一步了解山东、安徽2个省蔬菜产区2种病毒病的发生情况.结果表明,YLCV在山东省大部及安徽省局部地区已经发生扩散且中国所有的分离物仍属于IL株系.明确了ToCV在安徽地区发生,且统计发现2个省6个地区ToCV、TYLCV存在单独侵染及复合侵染.ToCV分离物均可分为2个大组,其中该研究所得到的分离物均与中国其他地区的分离物聚类到一组.

[目的]评价转cry1Ab/cry2Aj和G10evo-epsps基因玉米双抗12-5的杂交后代双抗12-5-21对亚洲玉米螟、黏虫、棉铃虫的抗性及对目标除草剂草甘膦的耐受性.[方法]分别在6叶期和花丝期、6叶期、花丝期对亚洲玉米螟、黏虫、棉铃虫进行田间人工接虫;自然条件下,收获期剖秆调查双抗12-5-21对鳞翅目害虫的抗性;在玉米5叶期分别喷施推荐剂量中剂量及2、4、6倍中剂量草甘膦,药后1、2、4周调查玉米受害情况.[结果]6叶期及花丝期,双抗12-5-21受亚洲玉米螟为害的虫害平均级值分别为1.12和1.07;6叶期,双抗12-5-21受黏虫为害的虫害平均级值为1.32;花丝期,双抗12-5-21受棉铃虫为害的虫害平均级值为0.02.双抗12-5-21对亚洲玉米螟、黏虫、棉铃虫抗性均达高抗水平.收获期剖秆结果显示,双抗12-5-21蛀孔数、活虫数及受害株率均显著低于对照玉米,对鳞翅目害虫控制效果达90％以上.喷施中剂量草甘膦,双抗12-5-21完全无受害症状;喷施2、4倍中剂量草甘膦后1周,双抗12-5-21表现轻微药害,2周后玉米完全无受害症状;双抗12-5-21喷施6倍中剂量的草甘膦后2周,受害率由1周的36.00％降为8.00％,新生叶片正常,4周后双抗12-5-21生长完全恢复正常,株高未受影响.[结论]转基因玉米双抗12-5-21田间对亚洲玉米螟、黏虫、棉铃虫的抗性均达高抗;双抗12-5-21能够耐受4倍中剂量草甘膦.

为获得能够防治棉花枯萎病的生防菌株,本试验从发生棉花枯萎病的棉田中筛选抑菌效果较好的生防菌株;通过形态学特征、生理生化特征与分子生物学方法对其进行菌种鉴定,并通过平板对峙法检测生防菌株粗提物对尖孢镰刀菌的防治效果及稳定性.结果筛选到一株抑菌效果较好的菌株JNJX-2,经鉴定为多粘类芽孢杆菌.该菌株的抑菌谱较广泛,对灰葡萄孢、离蠕孢菌、禾谷镰刀菌等均具有一定的抑制作用.该菌株可以产生几丁质酶、蛋白酶、果胶酶、纤维素酶.通过萃取与旋转蒸发相结合的方式,得到了该菌株的抑菌粗提物,其性质较为稳定,对温度、紫外线、蛋白酶不敏感,对碱性环境敏感.

玉米青枯病是一种严重影响玉米产量的土传病害,在世界各玉米种植区均有发生.玉米青枯病的病原复杂多样,不同地区差别很大.本研究连续3年(2014—2016年)对山东省6市玉米种植区青枯病的病原进行分离鉴定,发现山东省玉米青枯病主要为镰孢菌属(Fusarium spp.)和腐霉属(Pythium spp.)病原菌复合侵染所致,不同年份和地点的主要致病菌组成有一定差异.镰孢菌属病原菌主要为禾谷镰孢菌(F.gra-minearum)、拟轮枝镰孢菌(F.verticillioides)和层出镰孢菌(F.proliferatum),腐霉属病原菌主要为芒孢腐霉(P.aristosporum)和强雄腐霉(P.arrhenomanes).从全部分离物中选择3种有代表性的菌株(禾谷镰孢菌、拟轮枝镰孢菌、芒孢腐霉)进行致病力测定,结果显示禾谷镰孢菌致病力最强,对植株生长影响最大,拟轮枝镰孢菌次之,芒孢腐霉对植株生长的影响相对较小.本研究结果为制定山东省玉米青枯病综合防控方案奠定了基础.

HomePlant DiseaseVol. 104, No. 2First Report of ‘Candidatus Phytoplasma ziziphi’ Subgroup 16SrV-B Associated with Prunus salicina Witches’-Broom in China PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of ‘Candidatus Phytoplasma ziziphi’ Subgroup 16SrV-B Associated with Prunus salicina Witches’-Broom in ChinaR. Gao, S. K. Yang, H. H. Yan, J. Wang, H. Y. Wang, and X. B. LuR. Gao†Corresponding authors: R. Gao; E-mail Address: gaorui368@163.com and J. Wang; E-mail Address: jiewangsdau@163.comShandong Institute of Pomology, Taian, 271000, ChinaSearch for more papers by this author, S. K. YangInstitute of Plant Protection, Shandong Academy of Agricultural Sciences, Jinan, 250100, ChinaSearch for more papers by this author, H. H. YanDepartment of Plant Protection, Shandong Agricultural University, Taian, Shandong 271018, ChinaSearch for more papers by this author, J. Wang†Corresponding authors: R. Gao; E-mail Address: gaorui368@163.com and J. Wang; E-mail Address: jiewangsdau@163.comhttp://orcid.org/0000-0002-7991-8759Shandong Institute of Pomology, Taian, 271000, ChinaSearch for more papers by this author, H. Y. WangDepartment of Plant Protection, Shandong Agricultural University, Taian, Shandong 271018, ChinaSearch for more papers by this author, and X. B. LuInstitute of Plant Protection, Shandong Academy of Agricultural Sciences, Jinan, 250100, ChinaSearch for more papers by this author AffiliationsAuthors and Affiliations R. Gao1 † S. K. Yang2 H. H. Yan3 J. Wang1 † H. Y. Wang3 X. B. Lu2 1Shandong Institute of Pomology, Taian, 271000, China 2Institute of Plant Protection, Shandong Academy of Agricultural Sciences, Jinan, 250100, China 3Department of Plant Protection, Shandong Agricultural University, Taian, Shandong 271018, China Published Online:4 Dec 2019https://doi.org/10.1094/PDIS-06-19-1259-PDNAboutSections ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat The plum is one of the traditional fruit trees in China, with production reaching 6,791,974 metric tons in 2017, accounting for 57.8% of the world production (FAOSTAT, http://www.fao.org/faostat/en/#data/QC). In June 2018, Chinese plum trees (Prunus salicina L.) showing small leaves, witches’-broom, and shortened branches were found in two orchards (only two trees per orchard) located in the city of Qufu, Shandong Province, China. Leaf and stem tissues were collected from symptomatic and two symptomless trees. Under transmission electron microscopy, wall-less prokaryotes with pleomorphic shapes, comprising spheroidal, ovoid, dumbbell, and irregular tubular, mostly 150 to 500 nm across were observed in the phloem sieve tubes of symptomatic tissues. Indirect enzyme-linked immunosorbent assays were performed using the antibodies against immunodominant membrane protein (Imp) of jujube witches’-broom nky isolate. The Imp antibody can react with antigens from symptomatic plants but not with those from symptomless plants. The associated phytoplasma was designated as Prunus salicina witches’-broom (PSWB) phytoplasma. To further confirm the classification of PSWB phytoplasma, total DNA was extracted from each sample using the cetyltrimethylammonium bromide method. The 16S rRNA gene was amplified using phytoplasma-specific universal primers R16mF2/R16mR1 (Lee et al. 1998). Specific fragments, approximately 1.4 kb, were amplified from DNA samples isolated from four diseased plants tested but not from healthy-looking plum plants nor from the blank control (distilled water as a DNA template). The resultant fragments were then cloned into cloning vectors pMD18-T (Takara Bio, Dalian, China) and sequenced. All obtained sequences (1,433 bp) were identical, and one representative sequence was deposited in GenBank (accession no. MN080143). The 16S rRNA of PSWB phytoplasma was identical to those of the sweet cherry virescence phytoplasma (KF268424) and jujube witches’-broom isolate nky (CP025121) (Wang et al. 2018). Phylogenetic analysis of phytoplasma 16S rDNA sequences based on the maximum likelihood method using MEGA 6.0 software indicated the PSWB phytoplasma within the 16SrV-B and 16SrV-G cluster. The results of iPhyClassifier analysis (Zhao et al. 2009) showed that the R16F2n/R16R2 primed fragment patterns of PSWB phytoplasma, which were taken from the R16mF2/R16mR1 sequences, were identical and had a similarity coefficient (F) of 1.0 with that of the representative strain ‘Candidatus Phytoplasma ziziphi’ of 16SrV-B. European plum (Prunus domestica) witches’-broom was reported recently in Poland, and the etiological agent was ‘Ca. P. asteris’ representing subgroup I-B/L (Zwolińska et al. 2019). The 16SrV-B phytoplasma has not been previously associated with Chinese plum witches’-broom symptoms, although infection has been reported in cherry plum (Prunus cerasifera), causing small and rolled leaf symptoms in China (Hong et al. 2011). To our best knowledge, this is the first report of plums (P. salicina) infected by ‘Ca. P. ziziphi’ representing subgroup V-B in China. Although the disease was discovered by chance and sporadic, as the new natural plant host of phytoplasma, the plum plants could facilitate spread of the phytoplasma to other fruits crops, which has great significance in the pathogen’s epidemiology.The author(s) declare no conflict of interest.References:Hong, M., et al. 2011. J. Phytopathol. 159:57. https://doi.org/10.1111/j.1439-0434.2010.01722.x Crossref, ISI, Google ScholarLee, I. M., et al. 1998. Int. J. Syst. Evol. Microbiol. 48:1153. Google ScholarWang, J., et al. 2018. BMC Genomics 19:689. https://doi.org/10.1186/s12864-018-5075-1 Crossref, Google ScholarZhao, Y., et al. 2009. Int. J. Syst. Evol. Microbiol. 59:2582. https://doi.org/10.1099/ijs.0.010249-0 Crossref, ISI, Google ScholarZwolińska, A., et al. 2019. Plant Dis. 103:145. https://doi.org/10.1094/PDIS-06-18-0963-PDN Link, Google ScholarR. Gao and S. K. Yang contributed equally to this work.The author(s) declare no conflict of interest.Funding: This research was supported by the National Natural Science Foundation of China (31701899 and 31401718)DetailsFiguresLiterature CitedRelated Vol. 104, No. 2 February 2020SubscribeISSN:0191-2917e-ISSN:1943-7692 DownloadCaptionSymptom of maize ear rot caused by Fusarium sporotrichioides (B. B. Wang et al.). Photo credit: C. X. Duan. Systemic symptoms of alfalfa mosaic virus (AMV) isolate CaM on leaves of potato (X. Z. Nie et al.). Photo credit: X. Z. Nie. Metrics Downloaded 3,170 times Article History Issue Date: 31 Jan 2020Published: 4 Dec 2019First Look: 30 Aug 2019Accepted: 28 Aug 2019 Pages: 564-564 Information© 2020 The American Phytopathological SocietyFundingNational Natural Science Foundation of ChinaGrant/Award Number: 31701899Grant/Award Number: 31401718KeywordsplumPrunus salicina‘Candidatus Phytoplasma ziziphi’phytoplasma16SrV-BThe author(s) declare no conflict of interest.

Summary MicroRNAs (miRNAs) are a class of small noncoding RNAs that play important roles in plant growth and development as well as in stress responses. However, little is known about their regulatory functions affecting rice grain yield. We functionally characterized a novel miRNA in rice, OsmiR530, its target OsPL3, and its upstream regulator phytochrome‐interacting factor‐like 15 (OsPIL15). Their effects on rice yield were dissected comprehensively. We determined that OsmiR530 negatively regulates grain yield. Blocking OsmiR530 increases grain yield, whereas OsmiR530 overexpression significantly decreases grain size and panicle branching, leading to yield loss. Additionally, OsPL3, which encodes a PLUS3 domain‐containing protein, is targeted directly by OsmiR530. Knocking out OsPL3 decreases the grain yield. In‐depth analyses indicated that OsPIL15 activates OsMIR530 expression by directly binding to the G‐box elements in the promoter. Analyses of genetic variations suggested that the OsMIR530 locus has likely been subjected to artificial selection during rice breeding. The results presented herein reveal a novel OsPIL15–OsmiR530 module controlling rice grain yield, thus providing researchers with a new target for the breeding of high‐yielding rice.

采用田间试验研究了转基因玉米瑞丰1号-双抗-12-5(RF1-12-5)种植对根际土壤酶活性、微生物群落的影响,可为RF1-12-5的环境释放和商业化应用提供科学的安全性评价数据支持.研究结果表明:①在5个生育期内,RF1-12-5与其非转基因对照品种瑞丰1号(RF1)根际土壤碱性蛋白酶、脲酶和酸性转化酶活性均没有显著性差异;RF1-12-5根际土壤过氧化氢酶活性在收获期、碱性磷酸酶活性在乳熟期显著低于RF1,其他生育期差异不显著.②在5个生育期内,RF1-12-5与RF1根际土壤微生物群落的Shannon多样性指数、McIntosh均匀度指数和Simpson优势度指数均不存在显著性差异,主成分分析未发现RF1-12-5与RF1根际微生物功能多样性存在规律性差异.

从重庆市采集到表现花变叶症状的中国樱桃枝条样品,利用透射电镜在感病樱桃枝条韧皮部筛管细胞内观察到直径为200～500 nm的圆形或者近圆形的植原体粒子.提取感病和健康花瓣的总DNA,利用植原体16S rRNA基因及延伸因子rp基因通用引物进行PCR扩增,从感病植株中扩增得到了长度分别为1.4 kb的16S rRNA基因和1.2 kb的rp基因.序列一致率分析表明,樱桃花变叶植原体16S rRNA基因和rp基因均与四川甜樱桃花变绿植原体相应基因的核苷酸一致率最高,分别为100％和99.8％;16S rRNA基因相似系数分析表明,樱桃花变叶植原体与四川甜樱桃花变绿植原体、枣疯植原体的相似系数均为1.00;基于16S rRNA基因和rp基因构建系统进化树时发现,樱桃花变叶植原体均与16SrV-B亚组成员聚为一簇,该植原体属于16SrV组的B亚组.

[目的]探讨转cry1Ab/cry2Aj和G10evo-epsps基因玉米双抗505-12-5中外源Bt蛋白时空表达规律,对3种主要鳞翅目害虫亚洲玉米螟、黏虫和棉铃虫的抗性进行鉴定,为转基因玉米双抗505-12-5的商业化推广提供科学的数据支撑.[方法]Bt蛋白时空表达规律采用酶联免疫法(ELISA),田间抗虫性和室内抗虫性鉴定分别采用田间人工接虫和离体组织生测方法.[结果]在玉米6～8叶期,Bt含量表现为根>心叶>茎,分别为517.3、453.8和312.8 ng?g-1;大喇叭口期,Bt含量表现为心叶>根>茎,分别为353.3、281.3和232.9 ng?g-1;吐丝期,Bt含量表现为心叶>根>茎,分别为188.9、114.1和53.6 ng?g-1;乳熟期,根、茎和心叶含量相当,分别为178.0、160.3和185.4 ng?g-1;繁殖器官中Bt蛋白含量表现为籽粒>花丝>花粉>雄穗,分别为181.3、100.1、95.0和79.8 ng?g-1.室内抗虫性鉴定表明,转基因玉米双抗505-12-5心叶饲喂黏虫24 h,幼虫死亡率低,但48 h后达98.21％;双抗505-12-5心叶、花丝和籽粒饲喂玉米螟,24 h幼虫死亡率分别为87.37％、100％、100％;双抗505-12-5花丝饲喂棉铃虫,24 h幼虫死亡率达80.18％,48 h死亡率为92.45％.田间鉴定结果显示,转基因玉米双抗505-12-5在心叶期和雌穗期对玉米螟、心叶期对黏虫、雌穗期对棉铃虫的抗性均达高抗水平.[结论]转基因玉米双抗505-12-5各器官在不同生育期中均能表达Bt蛋白,尤其在鳞翅目害虫为害的主要时期6～8叶期和吐丝期及乳熟期,易受害器官中Bt蛋白表达量较高.转基因玉米双抗505-12-5田间及室内对3种鳞翅目害虫均表现了显著的抗性效果,具有推广应用的潜力.

Through filed experiments and indoor bioassay , the resistances of domestic transgenic maize hybride Ruifeng 1 -Double Resistance 12 -5(RF1 -12 -5) against three major maize lepidopteran pests , Pyrausta nubilalis, Mythimna separate and Helicoverpa armigera were studied.The results of the filed experi-ments showed that the resistance of RF1 -12 -5 against Ostrinia furnacalis and Helicoverpa armigera were in high level during the corresponding identification periods .The resistance against Mythimna separate was in moderate level during the whorl stage .The indoor bioassay results showed that RF1 -12 -5 had slower resist-ance against Ostrinia furnacalis at whorl stage.After feeding with RF1 -12 -5 leaves for 24,48 and 72 hours, the corrected mortality rates were respectively 63.97％, 77.14％ and 88.00％.At filamentous stage, the re-sistance was significant and the corrected mortality rate reached 100％ after 48 hours.During the grain period, the corrected mortality rates were respectively 68.86％, 83.96％ and 98.03％ after 24,48 and 72 hours.For Mythimna separate, at whorl stage, there was no obvious resistant effect after 24 hours, but the corrected mor-tality rates were 94.64％ and 100％ respectively after 48 and 72 hours.For Helicoverpa armigera, RF1 -12 -5 showed obvious resistance at filamentous stage and the corrected mortality rates were 87.59％ and 100％ after 24 and 48 hours respectively.In all,RF1 -12 -5 showed obvious field resistance against Ostrinia furnacalis and Helicoverpa armigera,but lower resistance against Mythimna separate.It showed lower resistance against Ostrinia furnacalis at whorl stage during indoor bioassay , but better resistance against Ostrinia furnaca-lis, Mythimna separate and Helicoverpa armigera at other stages.We concluded that RF1 -12 -5 had the po-tential for popularization and application in the future .