Volatile organic compounds(VOCs)play key roles in plant–plant communication,especially in response to pest attack.E-2-hexenal is an important component of VOCs,but it is unclear whether it can induce endog-enous plan...Volatile organic compounds(VOCs)play key roles in plant–plant communication,especially in response to pest attack.E-2-hexenal is an important component of VOCs,but it is unclear whether it can induce endog-enous plant resistance to insects.Here,we show that E-2-hexenal activates early signaling events in Ara-bidopsis(Arabidopsis thaliana)mesophyll cells,including an H2O2 burst at the plasma membrane,the directedflow of calcium ions,and an increase in cytosolic calcium concentration.Treatment of wild-type Arabidopsis plants with E-2-hexenal increases their resistance when challenged with the diamond-back moth Plutella xylostella L.,and this phenomenon is largely lost in the wrky46 mutant.Mechanistically,E-2-hexenal induces the expression of WRKY46 and MYC2,and the physical interaction of their encoded proteins was verified by yeast two-hybrid,firefly luciferase complementation imaging,and in vitro pull-down assays.The WRKY46–MYC2 complex directly binds to the promoter of RBOHD to promote its expres-sion,as demonstrated by luciferase reporter,yeast one-hybrid,chromatin immunoprecipitation,and electrophoretic mobility shift assays.This module also positively regulates the expression of E-2-hexenal-induced naringenin biosynthesis genes(TT4 and CHIL)and the accumulation of totalflavonoids,thereby modulating plant tolerance to insects.Together,our results highlight an important role for the WRKY46–MYC2 module in the E-2-hexenal-induced defense response of Arabidopsis,providing new in-sights into the mechanisms by which VOCs trigger plant defense responses.展开更多
针对现有贝叶斯算法应用于垃圾邮件过滤时,贝努利模型精度低、不能区分文本特征重要性、多项式模型计算量大、无关特征项浪费计算时间、对出现次数少的特征项反应敏感等缺点,提出RSSI(remove similar and sensitive items)特征模型。通...针对现有贝叶斯算法应用于垃圾邮件过滤时,贝努利模型精度低、不能区分文本特征重要性、多项式模型计算量大、无关特征项浪费计算时间、对出现次数少的特征项反应敏感等缺点,提出RSSI(remove similar and sensitive items)特征模型。通过计算并比较特征项出现的频率,去除无关和敏感特征项,减小运算量,增加正确率,减少过拟合。Matlab仿真结果表明,与现有的朴素贝叶斯算法(nave Bayes)和支持向量机(support vector machine,SVM)等算法相比,RSSI算法能显著减少分类时间,降低合法邮件被误判的概率。展开更多
Lunar soil preserves numerous fragments of meteorites impacting on the Moon,providing a unique opportunity to investigate the distribution of the types of projectiles over billions of years.Here we report the first di...Lunar soil preserves numerous fragments of meteorites impacting on the Moon,providing a unique opportunity to investigate the distribution of the types of projectiles over billions of years.Here we report the first discovery of an iron meteorite fragment from the Chang’e-5 lunar soil,which consists mainly of martensite(quenched from taenite),kamacite,and schreibersite,with a trace of pentlandite.The meteorite fragment is Ni-and P-rich,S-poor,and based on its mineral chemistry and bulk composition,can be classified into the IID-group,a rare and carbonaceous group of iron meteorite originating in the outer Solar System.This meteorite fragment experienced only limited partial melting followed by fast cooling,suggestive of efficient preservation of intact remnants of iron meteorites impacting on the porous lunar regolith.Alternatively,it is a relic of a low-velocity impact of submillimeter-sized metal grains originated from an IID-like iron meteorite.Our observations demonstrate that it is feasible to achieve the type distribution of meteorites impacting on the Moon via systematically analyzing a large number of metal grains separated from lunar soils,thus shedding light on the dynamic evolution of the Solar System.展开更多
基金supported by the National Natural Science Foundation of China (31270655).
文摘Volatile organic compounds(VOCs)play key roles in plant–plant communication,especially in response to pest attack.E-2-hexenal is an important component of VOCs,but it is unclear whether it can induce endog-enous plant resistance to insects.Here,we show that E-2-hexenal activates early signaling events in Ara-bidopsis(Arabidopsis thaliana)mesophyll cells,including an H2O2 burst at the plasma membrane,the directedflow of calcium ions,and an increase in cytosolic calcium concentration.Treatment of wild-type Arabidopsis plants with E-2-hexenal increases their resistance when challenged with the diamond-back moth Plutella xylostella L.,and this phenomenon is largely lost in the wrky46 mutant.Mechanistically,E-2-hexenal induces the expression of WRKY46 and MYC2,and the physical interaction of their encoded proteins was verified by yeast two-hybrid,firefly luciferase complementation imaging,and in vitro pull-down assays.The WRKY46–MYC2 complex directly binds to the promoter of RBOHD to promote its expres-sion,as demonstrated by luciferase reporter,yeast one-hybrid,chromatin immunoprecipitation,and electrophoretic mobility shift assays.This module also positively regulates the expression of E-2-hexenal-induced naringenin biosynthesis genes(TT4 and CHIL)and the accumulation of totalflavonoids,thereby modulating plant tolerance to insects.Together,our results highlight an important role for the WRKY46–MYC2 module in the E-2-hexenal-induced defense response of Arabidopsis,providing new in-sights into the mechanisms by which VOCs trigger plant defense responses.
文摘针对现有贝叶斯算法应用于垃圾邮件过滤时,贝努利模型精度低、不能区分文本特征重要性、多项式模型计算量大、无关特征项浪费计算时间、对出现次数少的特征项反应敏感等缺点,提出RSSI(remove similar and sensitive items)特征模型。通过计算并比较特征项出现的频率,去除无关和敏感特征项,减小运算量,增加正确率,减少过拟合。Matlab仿真结果表明,与现有的朴素贝叶斯算法(nave Bayes)和支持向量机(support vector machine,SVM)等算法相比,RSSI算法能显著减少分类时间,降低合法邮件被误判的概率。
基金supported by the National Natural Science Foundation of China(42230206,42241152,and 42103035)the Key Research Program of Frontier Sciences,Chinese Academy of Sciences(QYZDJ-SSW-DQC001).
文摘Lunar soil preserves numerous fragments of meteorites impacting on the Moon,providing a unique opportunity to investigate the distribution of the types of projectiles over billions of years.Here we report the first discovery of an iron meteorite fragment from the Chang’e-5 lunar soil,which consists mainly of martensite(quenched from taenite),kamacite,and schreibersite,with a trace of pentlandite.The meteorite fragment is Ni-and P-rich,S-poor,and based on its mineral chemistry and bulk composition,can be classified into the IID-group,a rare and carbonaceous group of iron meteorite originating in the outer Solar System.This meteorite fragment experienced only limited partial melting followed by fast cooling,suggestive of efficient preservation of intact remnants of iron meteorites impacting on the porous lunar regolith.Alternatively,it is a relic of a low-velocity impact of submillimeter-sized metal grains originated from an IID-like iron meteorite.Our observations demonstrate that it is feasible to achieve the type distribution of meteorites impacting on the Moon via systematically analyzing a large number of metal grains separated from lunar soils,thus shedding light on the dynamic evolution of the Solar System.
