摘要
在小麦品种西农1376与克旱21构建的近等基因系中发现一个自然突变的类病斑家系lm452。本研究对lm452的类病斑发生进程、生理生化特性、农艺性状、遗传分离规律等进行了研究。结果表明,类病斑最先发生于第一叶,颜色由白色渐变为黄褐色,呈条纹斑块状;类病斑数量随着植株生长发育进程逐渐增加,可蔓延至叶鞘。类病斑的发生受温度和光照影响,遮光可以避免或减轻类病斑的发生;低温和强光可加重类病斑发生。生理生化分析表明类病斑的形成伴随着超氧化物产生、可溶性蛋白质含量降低和细胞活性降低;突变体lm452的千粒重在田间和温室环境条件下均较表型正常姊妹系g451极显著降低。遗传分析表明lm452的类病斑性状受单个隐性核基因控制。上述结果为lm452类病斑基因的克隆和分子调控网络机制解析奠定了基础。
植物遭受病原体侵染时会诱发程序性细胞死亡(PCD, programmed cell death),以阻止病原体进一步入侵邻近细胞。在没有任何逆境、机械损伤或病原菌侵染的情况下,叶片呈现类似病原菌侵染的坏死斑的植株称为类病斑突变体(LMM, lesion mimic mutant
目前,在小
在农艺性状上,类病斑主要发生在突变体的叶片,不仅影响植株光合作用,也影响与产量相关的株高、穗粒数、千粒重等农艺性状。类病斑对上述性状的影响程度与类病斑发生时间和扩散面积有关,一般病斑出现时间早和扩散面积大的突变体产量性状受影响明显。水稻斑点叶突变体spl24的株高、穗长、穗粒数和千粒重均显著低于野生
在遗传机制上,已报道的类病斑基因包括隐性核基因、显性核基因、半显性核基因等3种类型。小麦类病斑大多为单个隐性核基因控制,如在三叶期出现黄色斑点的突变体LF201
在环境因素上,温度、光照、湿度等环境因素均可影响类病斑的发生。小麦突变体LF2010在遮光或低温条件下斑点产生较
在生理生化机制上,类病斑的发生常伴随ROS的升高。正常含量的ROS被认为是细胞内信号级联的次级信使,介导植物细胞内多种反应,包括叶表皮细胞的气孔关
类病斑突变体是研究植物光合作用、叶片衰老、植物抗病防卫机制、细胞程序性死亡等相关机制的理想材
本研究所用的小麦类病斑突变体lm452来源于西农1376(轮回亲本)与克旱21(供体亲本)构建的BC7F3近等基因系的分离后代,此后田间连续6年自交繁殖,类病斑性状均能稳定遗传。正常表型材料g451为lm452的姊妹系,二者系谱编号分别为KHD-BC7F3-8-3-1和KHD-BC7F3-8-3-2。配制lm452与g451的正反杂交组合,收获的F1、F2和F2∶3代种子用于遗传分析。
先将lm452的种子在室温浸泡12 h,然后转移至含双层湿润滤纸的培养皿中,在4 ℃冰箱中处理3 d以使种子萌发均一。将露白种子播种于直径14.5 cm的花盆,1株/盆,将花盆放置在培养箱中。为比较光照强度对类病斑发生的影响,在光照14 h、温度22 ℃,黑暗10 h、温度15℃ ,相对湿度85%的统一培养条件下,将光照强度设置3个梯度,LED灯光强的光合光子通量密度(PPFD,photosynthetic photon flux density)分别为100 µmol/(
为比较温度高低对类病斑发生的影响,在光强350 µmol/(
2021年秋季将g451和lm452种植在中国农业科学院作物科学研究所北京东圃场试验田(39°58′18.75″N, 116°20′28.64″E),行长1 m,行距25 cm,株距5 cm,共2行。为保证安全越冬,上述材料在冬季覆膜,并在返青后揭开。调查株高、有效分蘖数、穗长、穗粒数、千粒重等指标,有效分蘖的标准为结实粒数不少于5个。各个发育时期的判断依照Zadoks
g451和lm452分别种植27株,种植方法同1.2.1,培养条件为350 μmol/(
试验材料和取样方法同1.2.3。分别取0.1 g的g451和lm452叶片,将样品放入2 mL离心管中,液氮冷却后,用组织研磨机粉碎。按质量体积比1∶9向离心管中加入0.1 mol/L的磷酸盐缓冲液(pH 7.2),漩涡振荡2 min;3500 r/min离心10 min,取上清待测。参照丙二醛(MDA)含量、过氧化氢(H2O2)含量、过氧化氢酶(CAT)活性和超氧化物歧化酶(SOD)活性测定试剂盒(建成生物工程研究所,南京),以及可溶性蛋白含量(SP)测定试剂盒(碧云天生物技术有限公司,上海)的说明书进行操作;每个生理指标均为3个生物学重复。利用Excel 2019和SPSS 26.0进行数据统计和t检验分析。
lm452的类病斑发生受环境条件诱导。在培养箱生长条件下,类病斑最先发生于二叶期时的第一片叶,且位置不固定(

图1 lm452的类病斑发展过程和形态特征
Fig.1 Development and morphological characteristics of lesion in lm452
A:二叶期;B:三叶期;C:分蘖期,比例尺=2 cm;D:叶鞘,箭头所指为叶鞘上发生的类病斑;E:叶片,箭头所指为叶片上发生的类病斑。A、B、D和E的比例尺=1 cm
A: Two-leaf stage; B: Three-leaf stage; C: Tillering stage, scale bar=2 cm; D: Leaf sheath, the arrows point to the lesion mimic phenotype that occurs on the lm452 leaf sheath; E: Leaf, the arrows point to the lesion mimic phenotype that occurs on the lm452 leaves. The scale bar in A, B, D and E is 1 cm
lm452类病斑的发生速度和严重度受光照和温度影响。对相同发育阶段的叶片进行遮光与未遮光处理,遮光部位的叶片呈黄绿色无类病斑发生,而未遮光的叶片则发生类病斑。表明遮光可以避免或减弱类病斑的发生(

图2 光照和温度对lm452类病斑发展的影响
Fig.2 Effect of light and temperature on the development of lesion mimic in lm452
A:遮光(NL)和光照(L);B:3种光照强度;C:3种温度区间;比例尺=1 cm
A:Shading (NL,no light) and light (L) treatment; B: Three light intensities; C: Three temperature regimes; Scale bar=1 cm
在田间条件下,lm452因苗期叶片出现类病斑,冬季抗寒性较g451差(

图3 lm452和g451在田间和温室的生长情况
Fig.3 Growth of lm452 and g451 in fields and greenhouse
A:田间分蘖期;B:田间灌浆期,箭头所指为lm452叶鞘上发生的类病斑;C:温室灌浆期,比例尺=5 cm;D:田间收获籽粒,比例尺=1 cm;E:温室收获籽粒,比例尺=1 cm
A: Tillering stage in field; B: Grain filling stage in field, the arrows point to lesion mimic that occur on lm452 sheath; C: Grain filling stage in greenhouse, scale bar=5 cm; D: Grains harvested from fields, scale bar=1 cm; E: Grains harvested from greenhouse, scale bar=1 cm
环境 Environment | 材料 Materials | 株高(cm) Plant height | 有效分蘖数 Spike number per plant | 穗长(cm) Spike length | 千粒重(g) 1000-kernel weight | 穗粒数 Kernel number per spike |
---|---|---|---|---|---|---|
田间 Fields | lm452 | 59.2±0.5* | 9.0±0.2* | 10.5±0.2 | 41.60±1.10** | 33.2±7.09 |
g451 | 57.0±0.8 | 8.0±0.4 | 10.0±0.2 | 47.60±0.80 | 32.8±2.78 | |
温室 Green house | lm452 | 52.6±0.60** | 1.0±0** | 6.74±0.05** | 34.64±0.61** | 16.4±1.95** |
g451 | 49.5±1.69 | 2.0±0.45 | 8.00±0.39 | 41.04±1.80 | 25.2±0.84 |
数据为平均值±标准差; *表示在 P<0.05水平上差异显著, **表示在 P<0.01水平上差异显著,下同
Data are means ± SD; * indicates a significant difference at the P<0.05 level, and ** indicates a significant difference at the P<0.01 level,the same as below
在温室条件下,lm452单株有效分蘖数、穗长、千粒重、穗粒数分别较g451降低50.00%、15.75%、15.59%、34.92%,差异均达极显著水平(
类病斑突变体lm452和正常表型姊妹系g451的F1后代表现正常,未出现类病斑(

图4 五叶期突变体lm452、姊妹系g451和F1的叶片
Fig.4 Leaves of mutant lm452, sister line g451 and F1 at fifth-leaf stage
从左至右依次为幼苗的第1、第2、第3和第4叶,标尺=1 cm
The order from left to right is the first, second, third and fourth leaf of the seedlings, scale bar=1 cm
编号Number | 总株数Total plants | 正常株数 Normal plants | 分离株数Separation plants | 类病斑株数 Lesion mimic plants | 分离比 Separation ratio | P 值P value | |
---|---|---|---|---|---|---|---|
g451 | 49 | 49 | |||||
lm452 | 51 | 0 | 51 | ||||
g451/lm452 F1 | 10 | 10 | |||||
lm452/g451 F1 | 10 | 10 | |||||
F2 | 465 | 355 | 110 | 3.2∶1 | 0.448(3∶1) | 0.503 | |
F2:3 | 100 | 28 | 51 | 21 | 1.1∶2∶0.82 | 1(1∶2∶1) | 0.6 |
The value of
过氧化物酶可催化过氧化氢分解产生氧气,与二氨基联苯胺(DAB)作用后形成棕黄色沉淀,从而定位过氧化物酶的活性部位。lm452叶片经DAB染色后,发生类病斑的部位呈棕褐色,未发生类病斑的部位与g451叶片均为白色或浅黄色(

图5 lm452和g451的组织化学染色
Fig.5 Histochemical stainings of lm452 and g451
A:DAB染色,箭头所指为发生类病斑的部位,染色后呈棕褐色;B:伊文思蓝染色,箭头所指为发生类病斑的部位,染色后呈蓝色
A: DAB staining, the arrows point to the site where lesion mimic occur, which are tan after staining; B: Evans blue staining, the arrows point to the site where lesion mimic occur, which are blue after staining
在植物细胞内存在活性氧(ROS)清除酶系统将ROS含量稳定在正常水平。ROS过度积累会损害细胞结构,引发细胞程序性死亡,诱导ROS清除酶表达上调。lm452的过氧化氢酶(CAT)活性、超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量、过氧化氢(H2O2)含量均较g451显著增加,增幅分别达47.57%、62.09%、113.17%和29.23%;其中,CAT和SOD活性增加均达极显著水平(P=1×1

图6 突变体lm452与姊妹系g451的过氧化氢酶、超氧化物歧化酶、丙二醛、过氧化氢和可溶性蛋白含量
Fig.6 Catalase (CAT), superoxide dismutase (SOD), malondialdehyde (MDA), hydrogen peroxide (H2O2) and soluble protein (SP) between mutant lm452 and sister line g451
根据类病斑突变体的表型特征及其与细胞程序性死亡的关系,可将突变体分为细胞程序性死亡的抑制途径和激发途径两种类型。抑制途径所产生的突变体表现为类病斑突变体植株上的某一细胞一旦产生坏死,便迅速扩散到整个植
植物的生长发育受光照和温度等环境因素调
与叶绿素生物合成相关的关键酶活性改变可能会产生颜色变异的突
本研究中,lm452较g451的过氧化氢酶(CAT)、超氧化物歧化酶(SOD)活性和丙二醛(MDA)、过氧化氢(H2O2)含量都显著增加,而可溶性蛋白(SP)含量降低,表明类病斑的发生伴随着超氧化物产生和细胞活性降低。上述生理生化现象在植物类病斑的发生过程中十分普遍。在小麦类病斑突变体I3
本研究中的lm452类病斑性状受单个隐性核基因控制。目前已经报道的小麦类病斑突变体均由核基因控制。其中,Lm
参考文献
Kang S G, Lee K E, Singh M, Kumar P, Matin M N. Rice lesion mimic mutants (LMM): The current understanding of genetic mutations in the failure of ROS scavenging during lesion formation. Plants, 2021, 10 (8): 1598 [百度学术]
Wang L J, Pei Z Y, Tian Y C, He C Z. OsLSD1, a rice zinc finger protein, regulates programmed cell death and callus differentiation. Molecular Plant-Microbe Interactions, 2005, 18 (5): 375-384 [百度学术]
Nair S K, Tomar S M S. Genetical and anatomical analyses of a leaf flecking mutant in Triticum aestivum L. Euphytica, 2001, 121 (1): 53-58 [百度学术]
李倩倩,赵秋实,蒋宏宝,耿皆飞,刘录祥,张晓燕,谢彦周,王成社. 小麦白斑突变体I30的特征特性及遗传分析. 麦类作物学报,2017,37 (7): 871-879 [百度学术]
Li Q Q, Zhao Q S, Jiang H B, Geng J F, Liu L X, Zhang X Y, Xie Y Z, Wang C S. Characteristics and genetic analysis of wheat white spot mutant I30. Journal of Triticeae Crops, 2017, 37 (7): 871-879 [百度学术]
Fitzgerald H A, Chern M S, Navarre R, Ronald P C. Overexpression of (At) NPR1 in rice leads to a BTH-and environment-induced lesion-mimic/cell death phenotype. Molecular Plant-Microbe Interactions: MPMI, 2004, 17 (2): 140-151 [百度学术]
Michela L, Alessandra D F, Silvia B, Massimo D, Alberto F, Luca V, Roberto P, Monica B, Chiara T. A mutation in the FZL gene of Arabidopsis causing alteration in chloroplast morphology results in a lesion mimic phenotype. Journal of Experimental Botany, 2013, 64 (14): 4313-4328 [百度学术]
Hornbrook A R, Gardner C O. Genetic study of 'Necrotic Leaf Spot' mutation induced in an inbred line of maize (Zea mays L.) by thermal neutron irradiation of seed. Radiation Botany, 1970, 10 (2): 113-117 [百度学术]
Wolter M, Hollricher K, Salamini F, Schulze L P. The mlo resistance alleles to powdery mildew infection in barley trigger a developmentally controlled defence mimic phenotype. Molecular and General Genetics, 1993, 239 (1): 122-128 [百度学术]
杜丽芬,李明飞,刘录祥,王超杰,刘洋,许喜堂,邹淑芳,谢彦周,王成社. 一个化学诱变的小麦斑点叶突变体的生理和遗传分析. 作物学报,2014,40(6): 1020-1026 [百度学术]
Du L F, Li M F, Liu L X, Wang C J, Liu Y, Xu X T, Zou S F, Xie Y Z, Wang C S. Physiological characteristics and genetic analysis on a spotted-leaf wheat derived from chemical mutation. Acta Agronomica Sinica, 2014, 40 (6): 1020-1026 [百度学术]
Nair S K, Singh B, Tomar S M S. Inheritance and chromosomal location of flecking in a mutant C591 (M8) of wheat (Triticum aestivum L.). Indian Journal of Genetics and Plant Breeding, 2008, 68 (2): 108-112 [百度学术]
Luo P G, Ren Z L. Wheat leaf chlorosis controlled by a single recessive gene. Journal of Plant Physiology and Molecular Biology, 2006, 32 (3): 330-338 [百度学术]
Kamlofski C A, Antonelli E, Bender C, Jaskelioff M, Danna C H, Ugalde R, Acevedo A. A lesion‐mimic mutant of wheat with enhanced resistance to leaf rust. Plant Pathology, 2007, 56 (1): 46-54 [百度学术]
Li T, Bai G H. Lesion mimic associates with adult plant resistance to leaf rust infection in wheat. Theoretical and Applied Genetics, 2009, 119 (1): 13-21 [百度学术]
Wang F, Wu W Y, Wang D Z, Yang W L, Sun J Z, Liu D C, Zhang A M. Characterization and genetic analysis of a novel light-dependent lesion mimic mutant, lm3, showing adult-plant resistance to powdery mildew in common wheat. PLoS ONE, 2016, 11 (5): 155358 [百度学术]
Arumuganathan K, Earle E D. Nuclear DNA content of some important plant species. Plant Molecular Biology Report, 1991, 9: 208-218 [百度学术]
Chen Z, Chen T, Sathe A P, He Y, Zhang X B, Wu J L. Identification of a novel semi-dominant spotted-leaf mutant with enhanced resistance to Xanthomonas oryzae pv. oryzae in rice. International Journal of Molecular Sciences, 2018, 19 (12): 3766 [百度学术]
Chen P, Hu H T, Zhang Y, Wang Z W, Dong G J, Cui Y T, Qian Q, Ren D Y, Guo L B. Genetic analysis and fine-mapping of a new rice mutant, white and lesion mimic leaf. Plant Growth Regulation, 2018, 85 (3): 425-435 [百度学术]
Xiao G Q, Zhang H W, Lu X Y, Huang R F. Characterization and mapping of a novel light-dependent lesion mimic mutant lmm6 in rice (Oryza sativa L.). Journal of Integrative Agriculture, 2015, 14 (9): 1687-1696 [百度学术]
Yao Q, Zhou R H, Fu T H, Wu W R, Zhu Z D, Li A L, Jia J Z. Characterization and mapping of complementary lesion-mimic genes lm1 and lm2 in common wheat. Theoretical and Applied Genetics, 2009, 119 (6): 1005-1012 [百度学术]
Jambunathan N, Siani J M, McNellis T W. A humidity-sensitive arabidopsis copine mutant exhibits precocious cell death and increased disease resistance. The Plant Cell, 2001, 13 (10): 2225-2240 [百度学术]
Kwak J M, Mori I C, Pei Z M, Leonhardt N, Torres M A, Dangl J L, Bloom R E, Bodde S, Jones J D, Schroeder J I. NADPH oxidase AtrbohD and AtrbohF genes function in ROS-dependent ABA signaling in Arabidopsis. The EMBO Journal, 2003, 22 (11): 2623-2633 [百度学术]
Mittler R. Oxidative stress, antioxidants and stress tolerance. Trends in Plant Science, 2002, 7 (9): 405-410 [百度学术]
Joo J H, Bae Y S, Lee J S. Role of auxin-induced reactive oxygen species in root gravitropism. Plant Physiology, 2001, 126 (3): 1055-1060 [百度学术]
Torres M A, Dangl J L, Jones J D G. Arabidopsis gp9
Asada K. Production and action of active oxygen species in photosynthetic tissues. Boca Raton: CRC Press, 2019: 77-104 [百度学术]
Mittler R, Vanderauwera S, Gollery M, Van B F. Reactive oxygen gene network of plants. Trends in Plant Science, 2004, 9 (10): 490-498 [百度学术]
Lin A H, Wang Y Q, Tang J Y, Xue P, Li C L, Liu L C, Hu B, Yang F Q, Loake G J, Chu C C. Nitric oxide and protein S-nitrosylation are integral to hydrogen peroxide-induced leaf cell death in rice. Plant Physiology, 2012, 158 (1): 451-464 [百度学术]
马建, 李聪, 田荣, 唐华苹, 兰秀锦, 姚琦馥. 主要植物类病斑突变体研究进展及其对小麦相关研究的启示. 四川农业大学学报, 2022, 40 (5): 633-644 [百度学术]
Ma J, Li C, Tian R, Tang H P, Lan X J, Yao Q F. Research progress of lesion mimic mutants in main plants and its implication for wheat related studies. Journal of Sichuan Agricultural University, 2022, 40 (5): 633-644 [百度学术]
Zadoks J C, Chang T T, Konzak C F. A decimal code for the growth stages of cereals. Weed Research, 1974, 14 (6): 415-421 [百度学术]
Baker J C, Mock N M. An improved method for monitoring cell death in cell suspension and leaf disc assays using Evans blue. Plant Cell, Tissue and Organ Culture, 1994, 39 (1): 7-12 [百度学术]
Mittler R, Rizhsky L. Transgene-induced lesion mimic. Plant Molecular Biology,2000, 44 (3): 335-344 [百度学术]
张自刚,马小飞,张红霞,王震,张思妮,郭冬,张永鹏,马翎健. 小麦光温敏雄性不育系BNS育性转换与内源激素的关系研究. 植物遗传资源学报,2016,17 (5): 913-919 [百度学术]
Zhang Z G, Ma X F, Zhang H X, Wang Z, Zhang S N, Guo D, Zhang Y P, Ma L J. Relationship between fertility transition of thermo-photo-sensitive wheat male sterile line BNS and endogenous hormone contents in its developing ear. Journal of Plant Genetic Resources, 2016, 17 (5): 913-919 [百度学术]
Greenberg J T, Silverman F P, Liang H. Uncoupling salicylic acid-dependent cell death and defense-related responses from disease resistance in the arabidopsis mutant acd5. Genetics, 2000, 156 (1): 341-350 [百度学术]
Liu G, Wang L, Zhou Z, Leung H, Wang G L, He C. Physical mapping of a rice lesion mimic gene, Spl1, to a 70-kb segment of rice chromosome 12. Molecular Genetics and Genomics, 2004, 272 (1): 108-115 [百度学术]
杨颜榕,黄纤纤,赵亚男,汤佳玉,刘喜. 水稻叶色基因克隆与分子机制研究进展. 植物遗传资源学报,2020,21 (4): 794-803 [百度学术]
Yang Y R, Huang X X, Zhao Y N, Tang J Y, Liu X. Advances on gene isolation and molecular mechanism of rice leaf color genes. Journal of Plant Genetic Resources, 2020, 21 (4): 794-803 [百度学术]
Chen X F, Hao L, Pan J W, Zheng X X, Jiang G H, Jin Y, Gu Z M, Qian Q, Zhai W X, Ma B J. SPL5, a cell death and defense-related gene, encodes a putative splicing factor 3b subunit 3 (SF3b3) in rice. Molecular Breeding, 2012, 30 (2): 939-949 [百度学术]
Mori M, Tomita C, Sugimoto K, Hasegawa M, Hayashi N, Dubouzet J G, Ochiai H, Sekimoto H, Hirochika H, Kikuchi S. Isolation and molecular characterization of a spotted leaf 18 mutant by modified activation-tagging in rice. Plant Molecular Biology, 2007, 63 (6): 847-860 [百度学术]
Sun L T, Wang Y H, Liu L L, Wang C M, Gan T, Zhang Z Y, Wang Y L, Wang D, Niu M, Long W H, Li X H, Zheng M, Jiang L, Wan J M. Isolation and characterization of a spotted leaf 32 mutant with early leaf senescence and enhanced defense response in rice. Scientific Reports, 2017, 7 (1): 1-13 [百度学术]
Liu R, Lu J, Zheng S G, Du M, Zhang C H, Wang M X, Li Y F, Xing J Y, Wu Y, Zhang L. Molecular mapping of a novel lesion mimic gene(lm4)associated with enhanced resistance to stripe rust in bread wheat. BMC Genomic Data, 2021, 22 (1): 1-9 [百度学术]
Li C, Liu H, Wang J, Pan Q, Wang Y, Wu K Y, Jia P Y, Mu Y, Tang H P, Xu Q, Jiang Q T, Liu Y X, Qi P F, Zhang X J, Huang L, Chen G Y, Wang J R, Wei Y M, Zheng Y L, Gou L L, Yao Q F, Lan X J, Ma J. Characterization and fine mapping of a lesion mimic mutant (Lm5) with enhanced stripe rust and powdery mildew resistance in bread wheat (Triticum aestivum L.). Theoretical and Applied Genetics, 2022, 135 (2): 421-438 [百度学术]
Li T, Bai G H. Lesion mimic associates with adult plant resistance to leaf rust infection in wheat. Theoretical and Applied Genetics, 2009, 119 (1): 13-21 [百度学术]