Effects of different LED light wavelengths on the resistance of tomato against Botrytis cinerea and the corresponding physiological mechanisms

New types of light-emitting diode （LED） sources were applied to irradiate Botrytis cinerea mycelium and tomato leaves that were inoculated with B. cinerea to assess the effect of different LED light wavelengths on the infection of tomato with B. cinerea, to determine the optimum light wavelengths to control B. cinerea, and to explore the mechanism of LED influ- ence on the development of gray mold. The results showed that purple light and blue light irradiation significantly inhibited the growth of B. cinerea mycelium, and the inhibition rates were 22.3 and 15.16%, respectively, and purple light exhibited a better inhibitory effect than blue light. The lesion development of B. cinerea on tomato leaves was significantly inhibited upon irradiation with red and purple light with inhibition rates of 32.08 and 36.74%, respectively. Irradiation with red light inhibited the oxidative burst of superoxide anion （O2-） that was caused by infection with B. cinerea, and red light regulated the H2O2 content in the tomato leaf, which increased and rapidly returned to a lower level. In addition, red light irradiation improved the activity of superoxide dismutase （SOD）, catalase （CAT） and peroxidase （POD） in tomato leaves. However, purple light irradiation did not make tomato leaves exhibit this kind of physiological response. Therefore, red light and purple light can suppress gray mold in tomatoes, but the disease suppression mechanisms of these two types of LED light are different. In general, red light suppresses gray mold primarily by regulating the tomato defense mechanism for disease, whereas the suppression of tomato gray mold by purple light can be partially explained by the photo-inhibition of B. cinerea.

Transcriptome and metabolomics analysis revealed that CmWRKY49 regulating CmPSY1 promotes β-carotene accumulation in orange fleshed oriental melon

The flesh color of oriental melons is an important commercial trait that affects consumer preferences.To explore the mechanisms underlying the flesh color formation and regulation during fruit ripening,carotenoid-targeted metabolomic and RNA-seq analysis were conducted between white-fleshed(WF) and orange-fleshed(OF) oriental melon cultivars at different stages.The carotenoid-targeted metabolomic analysis indicated that β-carotene was the major metabolite that caused differences in flesh color between the two cultivars.Additionally,through KEGG pathway enrichment and weighted gene co-expression network(WGCNA) analysis,metabolic pathways and related transcription factors that are associated with carotenoid metabolism were selected and transcriptome data was verified using RT-qPCR.Finally,the yeast one hybrid and luciferase activity showed that the transcription factor CmWRKY49 could directly bind to the CmPSY1 promoter to activate its expression in the ’OF’ cultivar.Transient overexpression of CmWRKY49 in ’OF’ cultivar increased the β-carotene content,while the β-carotene content decreased when it was silenced in the same cultivar.This study provides insights into the underlying regulatory network of carotenoid metabolism in oriental melon fruit.

薄皮甜瓜9-脂氧合酶(9-LOX)类型的CmLOX09对逆境、激素和信号类物质的响应（英文）

目的:研究CmLOX09及其下游基因CmHPL和Cm AOS对逆境、激素和信号类物质的响应,进一步测定茉莉酸甲酯(Me JA)处理后叶片中绿叶挥发物的含量以及接种白粉病菌后叶片中茉莉酸含量的变化,探讨脂氧合酶(LOX)响应这两种胁迫的可能途径。创新点:通过对CmLOX09启动子中顺式作用原件的分析预测,首次研究薄皮甜瓜9-LOX类型的CmLOX09对机械损伤、激素、信号类物质以及生物胁迫的响应。方法:利用Plant CARE软件对Cm LOX09启动子响应元件进行预测分析(图S1);利用荧光定量聚合酶链反应(q RT-PCR)技术分析甜瓜在机械损伤、激素、信号类物质以及生物胁迫处理后叶片中CmLOX09、CmHPL和CmAOS的表达模式;利用气相色谱-质谱连用仪(GC-MS)测定叶片中绿叶挥发物的含量(图4);利用高效液相色谱-串联质谱法(HPLC-MS/MS)分析和测定叶片中茉莉酸的含量(图6)。结论:本研究结果显示:CmLOX09参与机械损伤、激素、信号类物质及白粉病菌的防御反应(图1~3,5)。9-LOX类型的CmLOX09可能通过氢过氧化物裂解酶(HPL)途径产生的绿叶挥发物(GLV)来响应Me JA(图4),并通过丙二烯合酶(AOS)途径产生的茉莉酸来响应真菌胁迫(图6)。综上所述,9-LOX类型的CmLOX09可能在生物和非生物胁迫反应中起重要作用。

线性电子传递和环式电子传递对缓解番茄亚高温强光胁迫的响应（英文）

目的:探讨特定高温和强光逆境下番茄叶片中的环式电子传递(CEF)和线性电子传递(LEF)的光保护机制。创新点:通过引入电子抑制剂的方法系统分析了CEF和LEF对亚高温强光胁迫的响应。方法:将品种为"辽园多丽"的番茄幼苗(n=160)平均分成四组(表1):组1,于常温常光照25°C,500μmol/(m^2·s)条件下培养并作为对照;组2,叶片喷施蒸馏水并在亚高温强光35°C,1000μmol/(m^2·s)(HH)条件下培养;组3,HH条件下叶片喷施100μmol/L敌草隆(DCMU,CEF抑制剂);组4,HH条件下叶片喷施60μmol/L甲基紫精(MV,LEF抑制剂)。在处理5 d及恢复10 d期间,分别测定番茄幼苗叶片的光能吸收、激发能分配、光系统活性、类囊体膜完整性和ATP酶活性等指标。结论:CEF和LEF通过一定程度上改善叶片光能吸收及激发能分配,并且维持类囊体膜较高完整性和ATP酶活性,从而维持光系统活性并减少光抑制和光破坏程度。