Tomato yellow leaf curl virus(TYLCV) is one of the most devastating viruses of cultivated tomatoes in the world,and it has become the limiting factor for production of tomatoes in both open field and protected cultivation systems.Recent years,TYLCV has resulted in great economic losses,and it is spreading towards north from south in China.In order to provide available information for tomato genetic improvement,the recent research advances on TYLCV in the following aspects were summarized:the taxonomy of TYLCV,the major sources and inheritance of resistance genes,tagging loci for resistance,the resistance breeding and genetic engineering.The strategies of using resistance genes and pyramid breeding were discussed in this paper.
Low temperature, as a kind of stress factor, often leads to tomato growth stagnation or yield reduction or even no harvest in production. At present, numerous genes have been shown to be involved in the regulation of cold resistance in the tomato. Complex regulatory mechanisms responding to low temperature stress in the tomato are still unclear in their details. In this study, six accessions of tomato (‘NL-7’, ‘NL-15’, ‘NL-18’, ‘NL-21, ‘NL-37’, and ‘NL-67’) with different cold tolerance were selected to detect the response to low temperature. The results showed that ‘NL-15’, ‘NL-18’, and ‘NL-21’ tomato accessions had cold tolerance under 8 °C/6 °C (day/night) for 15-day treatments. The TGS377 molecular marker, closely related to cold tolerance, was located on chromosome 1. The potential factors were identified and bioinformatics analysis within 50 kb upstream and downstream of TGS377. Fifteen genes were identified, and their structural analysis and functional annotation were also performed. The expression levels of Solyc01g008480 and Solyc01g150104 in the cold-sensitive tomato accessions (‘NL-7’, ‘NL-37’, and ‘NL-67’) were higher than that in the cold-tolerant accessions (‘NL-15’, ‘NL-18’ and ‘NL-21’). The expression levels of Solyc01g008390 and Solyc01g008410 in the cold-tolerant tomato ‘NL-18’ accession was significantly higher than that in the cold-sensitive accessions (‘NL-15’, ‘NL-18’, and ‘NL-21’). The results suggested that these genes may be involved in regulating low temperature response in the tomato, which lays a foundation for the search of potential cold response regulators in the tomato.
Drought is among the most challenging environmental restrictions to tomatoes (Solanum lycopersi-cum), which causes dehydration of the tissues and results in massive loss of yield. Breeding for dehydration-tolerant tomatoes is a pressing issue as a result of global climate change that leads to increased duration and frequency of droughts. However, the key genes involved in dehydration response and tolerance in tomato are not widely known, and genes that can be targeted for dehydration-tolerant tomato breeding remains to be discovered. Here, we compared phenotypes and transcriptomic profiles of tomato leaves between control and dehydration conditions. We show that dehydration decreased the relative water content of tomato leaves after 2 h of dehydration treatment; however, it promoted the malondialdehyde (MDA) content and ion leakage ratio after 4 h and 12 h of dehydration, respectively. Moreover, dehydration stress triggered oxidative stress as we detected significant increases in H
Abstract Background: Both drought and heat stress are serious global problems, leading to agricultural production loss. MicroRNAs (miRNAs) play important roles in plant species responding to individual drought and heat stress. However, the miRNAs and mRNAs in association with combined drought and heat in crops like tomato remains unclear. Results: We studied the crosstalk of miRNAs and their target genes in tomato plants grown under simultaneous drought and heat stress that frequently happen in field conditions. In total, 335 known miRNAs representing 55 miRNA families and 430 potential novel miRNAs were identified in Solanum lycopersicum L. using small RNA deep sequencing. Through expression analysis, miRNAs in association with drought, heat and the combination of these were investigated. In total, 61, 74 and 37 miRNAs were differentially regulated for combination (of both stresses) vs control, combination vs drought and combination vs heat, respectively. Target genes with different expression levels were found using degradome sequencing, which were mainly involved in transcription factor activity, sequence-specific DNA binding, transcription, regulation of transcription, nucleus, DNA binding etc . The quantitative real-time polymerase chain reaction (qRT-PCR) results confirmed the accuracy of sequencing. Conclusions: Our study serves as valuable knowledge on how crop adapted to combined drought and heat stress by regulating miRNAs and mRNAs, which provide information for crop improvement to deal with future climate changes.
Photosynthesis is involved in the essential process of transforming light energy into chemical energy. Although the interaction between photosynthesis and the circadian clock has been confirmed, the mechanism of how light intensity affects photosynthesis through the circadian clock remains unclear. Here, we propose a first computational model for circadian-clock-controlled photosynthesis, which consists of the light-sensitive protein P, the core oscillator, photosynthetic genes, and parameters involved in the process of photosynthesis. The model parameters were determined by minimizing the cost function ( [Formula: see text]), which is defined by the errors of expression levels, periods, and phases of the clock genes (
Tomato yellow leaf curl virus (TYLCV) causes serious yield reductions in China. The use of certain resistance genes in tomato varieties has alleviated the impact of the virus to a certain extent. Recently, varieties with the Ty-1, Ty-2, or Ty-3 genes lost their resistance to TYLCV in some areas in China. New genes should be introduced into tomato to maintain the resistance to TYLCV. Tomato line AVTO1227 has excellent resistance to disease due to the resistance gene ty-5. In this study, we screened different types of markers in a tomato F2 population to compare their accuracy and efficiency. The sequencing analysis results were consistent with the high resolution melting (HRM) marker genotype and field identification results. The result confirmed that the functional marker of ty-5 was accurate and reliable. The single nucleotide polymorphism-based HRM genotyping method established in this study can be used for the selection of breeding parent material, gene correlation analysis, and molecular marker-assisted breeding.
Both drought and heat stress are serious global problems, leading to agricultural production loss. MicroRNAs (miRNAs) play important roles in plant species responding to individual drought and heat stress. However, the miRNAs and mRNAs in association with combined drought and heat in crops like tomato remains unclear.We studied the crosstalk of miRNAs and their target genes in tomato plants grown under simultaneous drought and heat stress that frequently happen in field conditions. In total, 335 known miRNAs representing 55 miRNA families and 430 potential novel miRNAs were identified in Solanum lycopersicum L. using small RNA deep sequencing. Through expression analysis, miRNAs in association with drought, heat and the combination of these were investigated. In total, 61, 74 and 37 miRNAs were differentially regulated for combination (of both stresses) vs control, combination vs drought and combination vs heat, respectively. Target genes with different expression levels were found using degradome sequencing, which were mainly involved in transcription factor activity, sequence-specific DNA binding, transcription, regulation of transcription, nucleus, DNA binding etc. The quantitative real-time polymerase chain reaction (qRT-PCR) results confirmed the accuracy of sequencing.Our study serves as valuable knowledge on how crop adapted to combined drought and heat stress by regulating miRNAs and mRNAs, which provide information for crop improvement to deal with future climate changes.
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