广东地方稻种暹罗占抗稻瘟病基因分析

广谱抗病基因的利用是控制稻瘟病最有效和最经济的方法。来源于华南的地方稻种暹罗占对稻瘟病菌表现出广谱抗性,以普感品种丽江新团黑谷为轮回亲本选育的暹罗占近等基因系NIL-XLZ对测试的44个不同来源稻瘟病菌的抗性频率为84.4%,其抗谱优于广谱抗瘟基因Pi2、Piz,与抗瘟基因Pi9和Pi50相近。为进一步了解暹罗占抗稻瘟病的遗传基础,以感病品种广恢290为母本、暹罗占为父本,构建了广恢290/暹罗占的F2遗传分离群体。选取致病谱较广的稻瘟病菌代表菌株GD08-T19对来源于广恢290/暹罗占的F1与F2个体进行了抗病遗传分析,结果显示F1个体全表现抗病,1760个F2个体的抗感分离比率为4.06∶1,表明暹罗占至少含有一个显性的抗稻瘟病基因。利用分布于Pi2、Pi1、Pita座位附近的44对SSR引物,对构建的抗/感基因池及遗传分离个体进行了分析,将暹罗占含有的一个抗瘟基因定位于水稻第6染色体Pi2/Pi9/Pi50基因家族区域247 kb的范围内。抗菌谱分析、基因特异性分子标记检测及测序分析结果表明:暹罗占含有广谱抗瘟基因Pi50。本研究结果为暹罗占在水稻抗病育种上的应用提供了重要依据。     

分子标记辅助选择改良水稻不育系臻达A及其杂交种的稻瘟病抗性

水稻抗稻瘟病基因Pi25是一个遗传传递能力强的广谱抗性基因。本研究以携带抗稻瘟病基因Pi25的BL27为抗源供体,与优质、配合力强、感稻瘟病的水稻保持系臻达B为受体亲本进行杂交、回交创制水稻抗病保持系新种质,再与臻达A测交和回交进行不育系转育,结合分子标记辅助选择和农艺性状筛选,获得3个抗性基因纯合、农艺性状和开花习性均与臻达A相似的改良不育系株系。利用福建省近年来致病性代表的22个稻瘟病菌株对3个改良不育系及其15个杂交种进行抗性鉴定,3个改良不育系的抗性频率为95.45%~100%,15个杂交种的抗性频率均达75%以上,而原始对照臻达A及其杂交种的抗性频率仅为54.55%和40.91%~63.64%。自然病圃诱发鉴定表明,3个改良不育系的叶瘟和穗颈瘟均为0级,表现高抗,而对照臻达A的叶瘟为5级,穗颈瘟为7级,表现感病;15个杂交种均表现良好的稻瘟病抗性。进一步分析比较15个杂交种的产量、农艺性状和稻米品质表现,结果表明臻达A-Pi25-3改良不育系的综合性状表现最优,继续回交转育,于2015年育成了稻瘟病抗性强、配合力好、群体整齐和性状稳定的不育系,命名为157A。研究表明,抗稻瘟病基因Pi25不仅在水稻不育系臻达A的遗传背景下的抗性表达完全,且在不同水稻恢复系测交种的背景下同样表现出较高水平的抗性,说明抗性基因Pi25对不育系稻瘟病改良的效果明显。创制的新不育系157A的稻瘟病抗性显著提高,还基本保留了原来不育系高配合力等优良特性,为选育高产、优质、抗病杂交稻新品种提供了不育系新种质。     

应用分子标记技术改良京作1号的稻瘟病抗性

稻瘟病是危害水稻产量的重要生物胁迫之一。实践证明,解决这一问题的最有效方法是培育具广谱、持久稻瘟病抗性的品种并推广种植。本研究以优质、高产、感稻瘟病的京作1号为轮回亲本,与稻瘟病抗性基因Pi9、Pigm和pi21的供体材料进行杂交、回交和复交,结合分子标记辅助选择和农艺性状筛选,培育不同的单基因导入系和聚合系。苗期人工接种多个稻瘟病菌的结果显示,Pi9抗性改良系的抗性频率达到100%,Pigm抗性改良系平均为90%,均极显著高于轮回亲本京作1号的抗性频率,且农艺性状与京作1号基本一致。pi21抗性改良系的抗性水平与京作1号没有明显差异,单株产量极显著低于京作1号。与轮回亲本相比,Pi9和pi21聚合系的抗性频率极显著提高,达到93.33%,但单株产量明显降低。研究结果证实了Pi9和Pigm基因在大幅度提高抗瘟性的同时对主要农艺性状影响小,都具有较大的育种利用价值。基因pi21抗谱较窄,抗性不强,且可能存在对产量的负效应,不宜单独用来改良水稻品种的稻瘟病抗性,需要与抗性强的主基因聚合,通过多次回交和自交打破该基因与产量的不利连锁累赘。     

辽宁省主栽水稻品种抗稻瘟病基因的鉴定及分析

鉴定主栽水稻品种及育种骨干亲本的抗瘟基因型,有助于了解不同抗病基因在品种中的分布,为抗病品种选育及品种布局提供参考。本研究选取辽宁省24份水稻材料,根据7个抗稻瘟病基因的保守区设计引物,扩增各品种的编码区序列,对扩增的序列进行对比分析,鉴定各基因在24个品种中的分布情况。结果表明:辽宁省24个主栽水稻品种均不携带Pi21、Pi36、Pi37或其抗病等位基因,而Pid2、Pid3、Pita和Pik/Piks/Pikm/Pikp在24个品种中以不同突变类型及不同频率出现,其中,在2个品种中检测到Pid2抗病基因及Pid3的抗病等位基因;4个品种检测到Pita的抗病等位基因,Pita的等位基因中新发现的几处碱基突变并未影响抗病基因的功能;所有品种中均无与Pik及其复等位基因完全一致的序列,但利用携带AVR-pik的稻瘟病菌接种鉴定结果表明,辽粳454和沈农265携带的Pik等位基因可能仍具有抗病基因功能。     

国外引进水稻种质资源的稻瘟病抗性基因检测与评价

为了筛选出福建省水稻稻瘟病重发区育种中可利用的新抗性资源,在福建省上杭县对156份外引水稻种质资源进行了2年田间自然诱发鉴定,并对Pi2、Pi9、Pi5、Pi54、Pikm、Pita、Pia和Pib等8个稻瘟病抗性基因做了分子检测。结果表明:156份资源对苗瘟、叶瘟、穗颈瘟和综合抗性表现抗病的分别有10份、14份、29份和26份,且苗瘟抗性级别与叶瘟抗性级别(r=0.816,P<0.01)、苗瘟抗性级别与穗颈瘟抗性级别(r=0.347,P<0.01)、以及叶瘟抗性级别与穗颈瘟抗性级别(r=0.344,P<0.01),均呈极显著正相关。分子标记检测到携带稻瘟病抗性基因Pi9、Pi2、Pi54、Pikm、Pi5、Pib、Pia和Pita的水稻资源分别有1、6、20、22、37、88、101和106份,其中携带稻瘟病抗性基因Pi9和Pi2的水稻资源的抗性表现较好,表现抗病的超过60%,携带其他稻瘟病抗性基因的水稻资源表现抗病的均在50%以下;水稻资源携带0~6个稻瘟病抗性基因,随着携带抗性基因数目增加,抗病率呈上升趋势,综合抗性等级呈下降趋势。进一步研究发现,携带Pi9+Pi5+Pikm+Pia、Pi5+Pib+Pita+Pikm+Pia和Pi2+Pi54+Pib+Pita+Pikm+Pia等3个基因型的水稻资源,稻瘟病抗性较好。最后,筛选了8份稻瘟病抗性较好的材料,提供育种者参考、利用。     

抗稻瘟病水稻资源抗性基因Pita、Pib、Pi9以及Pikm的分布研究

利用抗稻瘟病水稻资源品种杂交,聚合多个抗性基因是培育持久抗稻瘟病水稻新品种的主要育种途径.利用分子标记技术对水稻抗性资源进行基因型鉴定是分子辅助聚合育种的基础.通过以亚华种业科学院稻瘟病病圃抗病水稻资源为材料,利用特异性分子标记对Pi9、Pita、Pib以及Pikm基因在水稻抗稻瘟病资源的分布进行了鉴定,初步建立了抗性基因数据库.同时对抗性基因及与抗性反应的相关性进行了探讨,结果表明以Pi9为主效基因,同时聚合Pita和Pib抗性基因能提高持久抗稻瘟病能力.     

利用分子标记辅助选择和花药培养改良光温敏不育系Y58S的稻瘟病抗性

Y58S是广泛应用的优良两系光温敏核不育系水稻品种.本研究通过分子标记辅助选择、花药培养与传统的回交技术相结合,将一全生育期广谱高抗稻瘟病基因R6导入Y58S,改良其稻瘟病抗性.根据改变激素的含量配制了4种诱导培养基,经比较发现激素配比为2,4-D 3 mg/L、KT 1 mg/L、NAA 2 mg/L的Y3培养基为Y58S背景材料花药培养的最佳培养基,其诱导率为15.08%,绿苗率为2.89%.本研究还获得1个含有R6基因的DH系,暂命名为YLH1,在远安自然诱发条件下稻瘟病抗性鉴定表明其分蘖期叶瘟抗性、抽穗期叶瘟抗性和穗颈瘟抗性均比对照Y58S显著提高.本研究表明花药培养和分子标记辅助选择相结合是改良光温敏核不育水稻稻瘟病抗性的快速、有效方法之一.     

辽宁地区水稻资源抗稻瘟病基因的检测分析

为了明确辽宁地区水稻资源中抗稻瘟病基因的分布情况及抗病效应,选取辽宁地区水稻资源176份,鉴定了抗稻瘟病基因pi21、Pi36、Pi37、Pita、Pid2、Pid3、Pi5及Pib在这些材料中的分布情况,并接种鉴定了这些材料对稻瘟病的抗性。结果表明:176份供试材料中,83份对稻瘟病表现抗病,栽培稻、杂草稻及农家种中抗病品种所占的比率分别为41.48%、1.14%及4.54%。抗稻瘟病基因pi21、Pi36和Pi37在所有参试材料中均未检测到,且分别有74份、49份、47份、52份及89份材料携带Pita、Pid2、Pid3、Pi5及Pib的抗病等位基因。抗病基因绝大部分分布在栽培种中,农家种和杂草稻中分布较少。不含有抗稻瘟病基因和只携带单个抗病基因的材料对稻瘟病的抗性均较差,而抗病基因聚合可不同程度提高材料的抗性。经检测,不含有本试验鉴定的pi21等8个已克隆抗病基因的材料共32份,其中表现抗病的占21.87%;只携带1个抗稻瘟病基因的材料为52份,表现抗病的占17.31%;携带2个抗稻瘟病基因的材料为39份,表现抗病的占69.23%,其中以携带Pita+Pi5的材料最多(14份),且均表现抗病;携带3个抗稻瘟病基因的材料为31份,表现抗病的占77.42%,以携带Pita+Pid3+Pi5的材料抗性最强;携带4个抗稻瘟病基因的水稻材料22份,表现抗病的占72.73%,携带5个抗病基因的水稻材料未检测到。     

定向改良超级早稻中早39稻瘟病抗性

稻瘟病是水稻生产中最具毁灭性的病害之一,稻瘟病菌生理小种变异快,抗性品种推广3～5年后抗性衰退风险较高,改良及培育抗稻瘟病菌新致病小种的品种是防治该病害最经济有效的方法。本研究以携带稻瘟病抗性基因Pi25的材料R6为供体亲本,超级早稻中早39为受体亲本和轮回亲本,通过杂交、回交和自交以及分子标记辅助选择技术,并结合室内喷雾接种、田间注射接种叶瘟以及病圃自然发病区穗颈瘟鉴定。综合考量抗性表型、基因型以及农艺性状,筛选出4个携带Pi25基因,叶瘟及穗颈瘟抗性较中早39提高,且农艺性状良好的株系FY82、FY90、FY125、FY137,同时对育成品系的系谱组成和抗性相关位点进行研究,初步阐明了育成品系较轮回亲本抗性水平提高的遗传基础。     

湖南桃江病圃稻瘟病菌的无毒基因及水稻抗瘟单基因联合抗性分析

【目的】鉴定湖南省桃江病圃稻瘟病菌无毒基因型,为合理搭配种植湖南省水稻抗瘟品种和抗病育种提供依据。【方法】在湖南桃江病圃采集水稻品种"丽江新团黑谷"(LTH)稻瘟菌病样,用单孢分离法分离稻瘟病菌单孢并纯化获得单孢菌株,用针刺离体法将菌株接种到以"LTH"为轮回亲本培育而成的24个含单抗瘟基因的水稻5叶期第5叶片上,对供试菌株进行无毒基因鉴定,并应用联合致病性系数和联合抗病性系数分析抗瘟基因组合间的互作。【结果】供试92个稻瘟病单孢菌株含有全部的24个无毒基因,对24个已知含单抗瘟基因的水稻材料表现出不同程度的毒力水平,含水稻抗瘟基因Pi-20对供试菌株抗菌频率最高,达54.35%;通过联合致病性系数和联合抗病性系数分析抗瘟基因组合间的互作,结果表明最佳搭配组合为Pi-20×Pi-k~s(RAC=0.28,PAC=0.23)。【结论】湖南省桃江病圃稻瘟病菌致病力较强,24个抗瘟基因多已感病化,含抗性基因Pi-20与Pi-k、Pi-k~s、Pi-3组合的水稻品种目前可在湖南省推广利用,但需研究引进新的抗瘟基因。     

云南两个县陆稻稻瘟病菌稻巨座壳交配型测定及致病性分析

2014年,自云南省沧源县及耿马县陆稻地方品种上分离99个稻瘟病菌稻巨座壳单孢菌株,采用4个已知交配型的标准菌株对其进行育性和交配型测定。结果表明,两地稻巨座壳菌株具较高的育性,平均可交配率高达90.8%,且可育菌株中,MAT1-1和MAT1-2菌株分别占60.9%和39.1%;分别随机对沧源县南撒村和班考村同一田块MAT1-1型和MAT1-2型可育两性菌株进行交配,均能发育形成成熟的子囊孢子,说明该陆稻地区稻巨座壳菌的可育菌株数量丰富,且于适宜条件极有可能产生有性世代;利用22个以丽江新团黑谷为背景、持有不同抗稻瘟病基因的单基因系对分离的99个稻巨座壳菌株的致病性进行测定,明确了不同菌株的致病性,且发现Pik-h、Piz-t、Pi5及Pi9基因表现出良好的抗性,平均抗病频率达到90.0%以上、是抗病育种的优异抗原;同时,菌株对特定抗性基因致病性的明确,也为选用不同菌株的组合开展有性杂交,构建遗传群体开展稻巨座壳菌无毒基因的克隆鉴定奠定了基础。     

Upgrading the genome of an elite japonica rice variety Kongyu 131 for lodging resistance improvement

Developing a new rice variety requires tremendous efforts and years of input. To improve the defect traits of the excellent varieties becomes more cost and time efficient than breeding a completely new variety. Kongyu 131 is a high-performing japonica variety with early maturity, high yield, wide adaptability and cold resistance, but the poor-lodging resistance hinders the industrial production of Kongyu 131 in the Northeastern China. In this study, we attempted to improve the lodging resistance of Kongyu 131 from perspectives of both gene and trait. On the one hand, by QTL analysis and fine mapping we discovered the candidate gene loci. The following CRISPR/Cas9 and transgenic complementation study confirmed that Sd1 dominated the lodging resistance and favourable allele was mined for precise introduction and improvement. On the other hand, the Sd1 allelic variant was identified in Kongyu 131 by sequence alignment, then introduced another excellent allelic variation by backcrossing. Then, the two new resulting Kongyu 131 went through the field evaluation under different environments, planting densities and nitrogen fertilizer conditions. The results showed that the plant height of upgraded Kongyu 131 was 17%–26% lower than Kongyu 131 without penalty in yield. This study demonstrated a precise and targeted way to update the rice genome and upgrade the elite rice varieties by improving only a few gene defects from the perspective of breeding.     

Gene diagnosis and targeted breeding for blast-resistant Kongyu 131 without changing regional adaptability

The fungus Magnaporthe oryzae threatens the rice production of Kongyu 131 (KY131), a leading japonica variety in Northeast China. In this study, two rice lines, KP1 and KP2-Hd1, were obtained by introgressing the blast resistance genes Pi1 and Pi2 into KY131, respectively. However, both lines headed later than KY131. RICE60K SNP array analysis showed that Hd1 closely linked to Pi2 was introgressed into KP2-Hd1, and the linkage drag of Hd1 was broken by recombination. On the other hand, no known flowering genes were introgressed into KP1. Gene diagnosis by resequencing six flowering genes showed that KP1 carried functional Hd16 and Ghd8 alleles. Due to its suppression role in heading under long-day conditions, Ghd8 was chosen as the target for gene editing to disrupt its function. Four sgRNAs targeting different sites within Ghd8 were utilized to induce large-deletion mutations, which were easy to detect via agarose gel electrophoresis. All the ghd8-mutated KP1 lines were resistant to rice blast disease and headed earlier than the control KP1, even than KY131, under natural long-day conditions, which ensures its growth in Northeast China. This study confirmed that a combination of gene diagnosis and targeted gene editing is a highly efficient way to quickly eliminate undesired traits in a breeding line.     

The identification of Pi50(t), a new member of the rice blast resistance Pi2/Pi9 multigene family

The deployment of broad-spectrum resistance genes is the most effective and economic means of controlling blast in rice. The cultivar Er-Ba-Zhan (EBZ) is a widely used donor of blast resistance in South China, with many cultivars derived from it displaying broad-spectrum resistance against blast. Mapping in a set of recombinant inbred lines bred from the cross between EBZ and the highly blast-susceptible cultivar Liangjiangxintuanheigu (LTH) identified in EBZ a blast resistance gene on each of chromosomes 1 (Pish), 6 (Pi2/Pi9) and 12 (Pita/Pita-2). The resistance spectrum and race specificity of the allele at Pi2/Pi9 were both different from those present in other known Pi2/Pi9 carriers. Fine-scale mapping based on a large number of susceptible EBZ?×?LTH F(2) and EBZ?×?LTH BC(1)F(2) segregants placed the gene within a 53-kb segment, which includes Pi2/Pi9. Sequence comparisons of the LRR motifs of the four functional NBS-LRR genes within Pi2/Pi9 revealed that the EBZ allele is distinct from other known Pi2/Pi9 alleles. As a result, the gene has been given the designation Pi50(t).     

Osa‐miR167d facilitates infection of Magnaporthe oryzae in rice

MicroRNAs (miRNAs) play important roles in rice response to Magnaporthe oryzae, the causative agent of rice blast disease. Studying the roles of rice miRNAs is of great significance for the disease control. Osa‐miR167d belongs to a conserved miRNA family targeting auxin responsive factor (ARF) genes that act in developmental and stress‐induced responses. Here, we show that Osa‐miR167d plays a negative role in rice immunity against M. oryzae by suppressing its target gene. The expression of Osa‐miR167d was significantly suppressed in a resistant accession at and after 24 h post inoculation (hpi), however, its expression was significantly increased at 24 hpi in the susceptible accession upon M. oryzae infection. Transgenic rice lines over‐expressing Osa‐miR167d were highly susceptible to multiple blast fungal strains. By contrast, transgenic lines expressing a target mimicry to block Osa‐miR167d enhanced resistance to rice blast disease. In addition, knocking out the target gene ARF12 led to hyper‐susceptibility to multiple blast fungal strains. Taken together, our results indicate that Osa‐miR167d negatively regulate rice immunity to facilitate the infection of M. oryzae by downregulating ARF12. Thus, Osa‐miR167d‐ARF12 regulatory module could be valuable in improvement of blast‐disease resistance.     

粳稻子预44中稻瘟病数量抗性位点分析

稻瘟病是世界范围内影响水稻(Oryza sativa)生产的主要病害。抗稻瘟病基因的发掘和育种利用是控制稻瘟病经济、环保的有效措施。为了揭示云南地方水稻品种子预44广谱持久抗瘟机制, 利用江南香糯和子预44杂交构建的F₇重组自交群体, 采用苗期稻瘟病菌自然诱发接种法, 通过调查田间抗瘟性表型数据, 结合基因型数据对子预44中的数量抗瘟性位点进行了分析。结果表明, 在连锁系数(logarithm of odds, LOD)大于2.0的域值上, 共检测出13个QTLs, 分别位于第1、2、6、8、12号染色体上。不同位点表型贡献值差异较大, 范围为5.8%-21.9%, 其中8号染色体上标记RM72-RM404之间的QTLs可解释约61.9%的表型变异, 很可能为一个主效抗瘟QTL位点。多个位点的主效和微效抗性相结合可能是子预44持久稻瘟病抗性的分子基础。     

粳稻子预44抗LP11稻瘟病菌基因Pizy6(t)的定位

稻瘟病是世界范围内严重威胁水稻(Oryza sativa)生产可持续发展的主要病害之一,每年造成10%–30%的水稻产量损失。抗瘟水稻品种的培育和育种利用是解决稻瘟病危害最经济有效的方法。对新的致病性菌株进行分离和筛选是定位与克隆抗病新基因及抗病育种的基础。选择分离自不同稻瘟病发生重灾区的单孢菌株,对广谱抗瘟水稻子预44和感病水稻江南香糯进行致病性鉴定,筛选出两材料间致病性差异明显的5个菌株;进一步利用子预44、湘资3150、9311、日本晴、丽江新团黑谷、中花11、TP309和江南香糯8个抗瘟性不同的水稻材料,对筛选的菌株进行致病性鉴定。结果显示,LP11能使广谱抗瘟籼稻湘资3150严重发病,推测其很可能是新进化出来的强致病菌株。利用子预44和江南香糯杂交构建的F2群体进行抗性遗传分析,结果表明子预44对LP11菌株的抗性是由单显性基因控制。利用SSR分子标记和图位克隆方法在子预44中定位了1个抗稻瘟病基因Pizy6(t)。研究结果不仅为抗病相关研究提供了有价值的新菌株,而且为子预44中抗稻瘟病基因Pizy6(t)的克隆奠定了基础。     

Genetic control of rice blast resistance in the durably resistant cultivar Gumei 2 against multiple isolates

To further our understanding of the genetic control of blast resistance in rice cultivar Gumei 2 and, consequently, to facilitate the utilization of this durably blast-resistant cultivar, we studied 304 recombinant inbred lines of indica rice cross Zhong 156/Gumei 2 and a linkage map comprising 181 markers. An analysis of segregation for resistance against five isolates of rice blast suggested that one gene cluster and three additional major genes that are independently inherited are responsible for the complete resistance of Gumei 2. The gene cluster was located to chromosome 6 and includes two genes mapped previously, Pi25(t), against Chinese rice blast isolate 92-183 (race ZC15) and Pi26(t) against Philippine rice blast isolate Ca89 (lineage 4), and a gene for resistance against Philippine rice blast isolate 92330-5 (lineage 17). Of the two genes conferring resistance against the Philippine isolates V86013 (lineage 15) and C923-39 (lineage 46), we identified one as Pi26(t) and mapped the other onto the distal end of chromosome 2 where Pib is located. We used three components of partial blast resistance, percentage diseased leaf area (DLA), lesion number and lesion size, all measured in the greenhouse, to measure the degree of susceptibility to isolates Ca89 and C923-39 and subsequently identified nine and eight quantitative trait loci (QTLs), respectively. Epistasis was determined to play an important role in partial resistance against Ca89. Using DLA measured on lines susceptible in a blast nursery, we detected six QTLs. While different QTLs were detected for partial resistance to Ca89 and C923-39, respectively, most were involved in the partial resistance in the field. Our results suggest that the blast resistance in Gumei 2 is controlled by multiple major genes and minor genes with epistatic effects.     

稻镰状瓶霉对水稻白叶枯病的生物防治

本文研究了野生稻暗色有隔内生真菌稻镰状瓶霉与水稻的共生关系,通过根部接种DsRED荧光标记菌株,观察稻镰状瓶霉在水稻根系内的定殖,并对其抗白叶枯病特性进行调查,结果发现：经叶部接种白叶枯病菌后,对照组发病严重,病级集中在7级和9级,分别占比43.33%和34.67%,病情指数为79.26;相比之下,接种了稻镰状瓶霉的水稻植株发病较轻,叶片病斑面积小,并伴随零星黑色过敏性坏死斑出现,未发病植株占8%,72%的植株病级为1级,病情指数仅为15.26。稻镰状瓶霉对水稻白叶枯病的防治效果达到80.75%。稻镰状瓶霉的定殖能够引起叶片中超氧化物歧化酶、过氧化氢酶和过氧化物酶活性极显著提高,分别是对照组的5.26、12.08和10.53倍;诱导PR1a和PR1b显著上调表达8.71和3.37倍,AOS、OsSAUR2和EL5基因显著下调表达0.28、0.57和0.65倍。利用野生稻内生真菌防控水稻白叶枯病,在国内外尚属首次,可为水稻白叶枯病的生物防治提供新途径。