摘要
【目的】探究马铃薯内生细菌Bt缓解宿主干旱胁迫的生理响应,为内生细菌缓解马铃薯干旱胁迫的机理及抗旱管理提供理论依据。【方法】对1株分离培养自马铃薯叶片的内生细菌Bt,利用形态学和分子测序方法进行种类鉴定,并测定该菌株在低水势下的生存能力及代谢产物活性;采用盆栽试验,利用PEG-6000进行模拟干旱胁迫处理,干旱处理分为正常浇水(CK:PEG-6000浓度为0)、中度干旱胁迫(D1:PEG-6000浓度为20%)和重度干旱胁迫(D2:PEG-6000浓度为25%),研究接种Bt内生菌株在干旱胁迫下对马铃薯的促生作用和生理响应,并对其进行抗旱性评价。【结果】分子鉴定结果表明,Bt为芽孢杆菌属(Bacillus)苏云金杆菌(Bacillus thuringiensis),该菌株具在低水势下生存的能力、产IAA活性和ACC脱氨酶活性,干旱胁迫下接种Bt对马铃薯促生效果明显。与CK相比,马铃薯植株的根长有所增加但不显著(P>0.05,下同),株高和茎粗在D2处理下较CK分别增加16.7%和16.0%;在D1、D2处理下接种Bt后,植株叶片相对叶绿素含量(SPAD值)、气孔导度较CK分别提高11.1%、20.5%和11.2%、77.8%;在D2处理下,接种Bt的植株净光合速率较CK增加34.3%;在D1、D2处理下马铃薯植株内脯氨酸含量较CK分别增加24.8%和25.2%,在D1处理下接种Bt后马铃薯植株可溶性蛋白含量较CK增加33.0%,在D1、D2处理下,接种Bt后丙二醛(MDA)含量较CK显著降低37.1%和14.9%(P<0.05);在干旱处理下接种Bt后,植株CAT活性较CK有所提高但不显著,过氧化物酶(POD)活性在D1处理下较CK提高26.4%,超氧化物歧化酶(SOD)活性在D1、D2处理较CK分别提高57.9%和35.1%。通过模糊数学隶属函数法对不同处理下马铃薯抗旱性进行综合评价,抗旱性强弱依次为D2-Bt、CK-Bt、D1-Bt、D2-W、CK-W和D1-W。【结论】马铃薯内生细菌Bt通过产生IAA和ACC脱氨酶来促进马铃薯生长发育,缓解马铃薯干旱胁迫。
【Objective】To investigate the physiological response of the endophytic bacterium Bt in potato to alleviate host drought stress,and to provide a theoretical basis for the mechanism of endophytic bacterial drought stress alleviation and drought management in potato.【Method】An endophytic strain of Bt isolated from potato leaves was identified by morphological and molecular sequencing methods,and the survival ability and metabolite activity of the strain were deter-mined under low water potential;a pot experiment was conducted using PEG-6000 to simulate drought stress treatment,with drought treatments divided into normal watering(CK:PEG-6000 concentration of 0),moderate drought stress(D1:PEG-6000 concentration of 20%)and severe drought stress(D2:PEG-6000 concentration of 25%)were used to study the pro-growth effect and physiological response of inoculated Bt endophytic strain on potato under drought stress,and to evaluate their drought resistance.【Result】Molecular identification of Bt as Bacillus thuringiensis of Bacillus,a strain with the ability to survive under low water potential,IAA-producing activity and ACC deaminase activity,showed that inoculation of Bt under drought stress had obvious effect on potato growth promotion.Compared with CK,the root length of potato plants increased but not significantly(P>0.05,the same below),plant height and stem thickness increased by 16.7%and 16.0%respectively under D2 treatment compared with CK;the relative chlorophyll content(SPAD value)and stomatal conductance of plant leaves increased by 11.1%,20.5%and 11.2%,77.8%respectively after Bt inoculation un-der D1 and D2 treatments compared with CK.The net photosynthetic rate of plants inoculated with Bt increased by 34.3%compared with CK under D2 treatment;the proline content in potato plants increased by 24.8%and 25.2%compared with CK under D1 and D2 treatments respectively,and the soluble protein content of potato plants increased by 33.0%com-pared with CK after inoculation with Bt under D1 treatment.In D1 and D2 treatments,malondialdehyde(MDA)content was significantly reduced by 37.1%and 14.9%compared to CK(P<0.05);CAT activity of plants inoculated with Bt un-der drought treatment increased but not significantly compared to CK,peroxidase(POD)activity increased by 26.4%compared to CK under D1 treatment,and superoxide dismutase(SOD)activity increased by 57.9%and 35.1%compared to CK under D1 and D2 treatments respectively.The drought resistance of potatoes under different treatments was evaluated comprehensively by the fuzzy mathematical affiliation function method,and the drought resistance was D2-Bt,CK-Bt,D1-Bt,D2-W,CK-W and D1-W in order.【Conclusion】The potato endophytic bacterium Bt promotes potato growth and development by producing IAA and ACC deaminases to alleviate drought stress in potato.
作者
吉泽
李俊逸
姚遥
祝春月
杨金睿
陈斌
肖关丽
JI Ze;LI Jun-yi;YAO Yao;ZHU Chun-yue;YANG Jin-rui;CHEN Bin;XIAO Guan-li(College of Agronomy and Biotechnology,Yunnan Agricultural University,Kunming,Yunnan 650201,China;College of Plant Protection,Yunnan Agricultural University,Kunming,Yunnan 650201,China)
出处
《南方农业学报》
CAS
CSCD
北大核心
2022年第12期3389-3399,共11页
Journal of Southern Agriculture
基金
云南省重大科技专项(2019ZG00902)。
关键词
马铃薯
内生细菌
干旱胁迫
生理特性
potato
endophytic bacteria
drought stress
physiological characteristics