Effects of the Chloroplast Fructose-1,6-Bisphosphate Aldolase Gene on Growth and Low-Temperature Tolerance of Tomato

Tomato (Solanum lycopersicum) is one of the most important greenhouse vegetables, with a large cultivated area across the world. However, in northern China, tomato plants often suffer from low-temperature stress in solar greenhouse cultivation, which affects plant growth and development and results in economic losses. We previously found that a chloroplast aldolase gene in tomato, SlFBA4, plays an important role in the Calvin-Benson cycle (CBC), and its expression level and activity can be significantly altered when subjected to low-temperature stress. To further study the function of SlFBA4 in the photosynthesis and chilling tolerance of tomato, we obtained transgenic tomato plants by the over-expression and RNA interference (RNAi) of SlFBA4. The over-expression of SlFBA4 led to higher fructose-1,6-bisphosphate aldolase activity, net photosynthetic rate (Pn) and activity of other enzymes in the CBC than wild type. Opposite results were observed in the RNAi lines. Moreover, an increase in thousand-seed weight, plant height, stem diameter and germination rate in optimal and sub-optimal temperatures was observed in the over-expression lines, while opposite effects were observed in the RNAi lines. Furthermore, over-expression of SlFBA4 increased Pn and enzyme activity and decreased malonaldehyde (MDA) content under chilling conditions. On the other hand, Pn and MDA content were more severely influenced by chilling stress in the RNAi lines. These results indicate that SlFBA4 plays an important role in tomato growth and tolerance to chilling stress.

Morphological, Physiological and Biochemical Response to Low Temperature Stress in Tomato (Solanum lycopersicum L.): A Review

Growth and productivity are traumatized by the low temperature that triggers a series of physiological, morphological, molecular and biochemical changes in plants that eventually disturb plant life. Most of the cultivable lands of the world are adversely affected by temperature stress conditions which have an adverse impact on global tomato productivity. Plants undergo several water related metabolic activities for their survival during cold stress conditions. Understanding the morphological, physiological and biochemical reactions to low temperature is essential for a comprehensive view of the perception of tomato plant tolerant mechanism. This review reports some aspects of low temperature inflated changes in physiological and biochemical in the tomato plant. Low temperature stress influences the reproductive phases of plants with delayed flowering which enhance pollen sterility resultant drastically affects the harvest yield. It also decreases the capacity and efficiency of photosynthesis through changes in gas exchange, pigment content, chloroplast development and decline in chlorophyll fluorescence photosynthetic attributes. Amassing of osmoprotectant is another adaptive mechanism in plants exposed to low temperatures stress, as essential metabolites directly participate in the osmotic adjustment. Furthermore, low temperature stress enhanced the production of reactive oxygen species (ROS) which may oxidize lipids, proteins and nucleic acids which bring in distortion at the level of the cell. At the point when extreme reactive oxygen species produced, plants synthesize antioxidant enzymes and osmoprotectants that quench the abundance of reactive oxygen species. These reviews focus on the capacity and techniques of the tomato plant to react low temperature stress.

Integrated Isoform Sequencing and Dynamic Transcriptome Analysis Reveals Diverse Transcripts Responsible for Low Temperature Stress at Anther Meiosis Stage in Rice

Low temperatures stress is one of the important factors limiting rice yield, especially during rice anther development, and can cause pollen sterility and decrease grain yield. In our study, low-temperature stress decreased pollen viability and spikelet fertility by affecting the sugar, nitrogen and amino acid contents of anthers. We performed RNA-seq and ISO-seq experiments to study the genome-wide transcript expression profiles in low-temperature anthers. A total of 4,859 differentially expressed transcripts were detected between the low-temperature and control groups. Gene ontology enrichment analysis revealed significant terms related to cold tolerance. Hexokinase and glutamate decarboxylase participating in starch and sucrose metabolism may play important roles in the response to cold stress. Using weighted gene co-expression network analysis, nine hub transcripts were found that could improve cold tolerance throughout the meiosis period of rice: Os02t0219000-01 (interferon-related developmental regulator protein), Os01t0218350-00 (tetratricopeptide repeat-containing thioredoxin), Os08t0197700-00 (luminal-binding protein 5), Os11t0200000-01 (histone deacetylase 19), Os03t0758700-01 (WD40 repeat domain-containing protein), Os06t0220500-01 (7-deoxyloganetin glucosyltransferase), Pacbio.T01382 (sucrose synthase 1), Os01t0172400-01 (phospholipase D alpha 1), and Os01t0261200-01 (NAC domain-containing protein 74). In the PPI network, the protein minichromosome maintenance 4 (MCM4) may play an important role in DNA replication induced by cold stress.

Assessment of cold stress tolerance in maize through quantitative trait locus, genome-wide association study and transcriptome analysis

Genome-wide association study (GWAS) has become a widely accepted strategy for decoding genotype phenotype associations in many species thanks to advances in next-generation sequencing (NGS) technologies. Maize is an ideal crop for GWAS and significant progress has been made in the last decade. This review summarizes current GWAS efforts in maize functional genomics research and discusses future prospects in the omics era. The general goal of GWAS is to link genotypic variations to corresponding differences in phenotype using the most appropriate statistical model in a given population. The current review also presents perspectives for optimizing GWAS design and analysis. GWAS analysis of data from RNA, protein, and metabolite-based omics studies is discussed, along with new models and new population designs that will identify causes of phenotypic variation that have been hidden to date. The detailed that low temperature in maize seedlings altogether restricts germination and seedlings' development and destabilizes the cancer prevention agent safeguard component. Cold pressure adversely influences root morphology, photosystem II (PS II) effectiveness, chlorophyll substance, and leaf region. A short scene of low temperature stress (for example, under 10 °C for 7 days) during the V6–V9 maize development stages can fundamentally defer the anthesis commencement. Among the morphological reactions by focused on maize plants, low temperature stress causes strange tuft development in maize, along these lines influencing the fertilization and grain filling measures. Hence, problematic temperatures can cause a genuine yield decrease if happening at basic conceptive stages, as plants allocate over half of their photosynthesis to foster grains during this stage until physiological development. Low temperature stress fundamentally diminishes the plant stature and absolute yield biomass of maize. Leaf improvement turns out to be delayed in chilly focused on plants because of a drawn-out cell cycle and diminished pace of mitosis. The joint and continuous efforts of the whole community will enhance our understanding of maize quantitative traits and boost crop molecular breeding designs.

Photosynthesis and antioxidant metabolism modulate the low-temperature resistance of seed germination in maize

Spring maize is usually subjected to low-temperature stress during seed germination, which retards seedling growth even if under a suitable temperature. However, the mechanism underlying maize seed germination under low-temperature stress modulating seedling growth after being transferred to normal temperature is still ambiguous. In this study, we used two maize inbred lines with different low-temperature resistance (SM and RM) to investigate the mechanism. The results showed that the SM line had higher lipid peroxidation and lower total antioxidant capacity and germination percentage than the RM line under low-temperature stress, which indicated that the SM line was more vulnerable to low-temperature stress. Further transcriptome analysis revealed that seed germination under low-temperature stress caused down-regulation of photosynthesis related gene ontology (GO) terms in two lines. Moreover, the SM line displayed down-regulation of ribosome and superoxide dismutase (SOD) related genes, whereas genes involved in SOD and vitamin B6 were up-regulated in the RM line. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed that photosynthesis and antioxidant metabolism related pathways played important roles in seed germination in response to low-temperature stress, and the photosynthetic system displayed a higher damage degree in the SM line. Both qRT-PCR and physiological characteristics experiments showed similar results with transcriptome data. Taken together, we propose a model for maize seed germination in response to low-temperature stress.

Cloning and Functional Analysis of Expansin TaEXPA9 Homologs in Winter Wheat in Frigid Regions

BackgroundLow temperature is an important factor that influences the ability of winter wheat to safely overwinter. Excessive low temperatures restrict the regrowth of winter wheat, thus decreasing agricultural output. Non-enzymatic expansins, which are related to plant growth, have been reported to respond to drought, salinity, and low temperature stress. We obtained an expansin gene, TaEXPA9, that is induced by low temperature from a transcriptome analysis of ‘Dongnong winter wheat no. 2’—a winter wheat with high cold hardiness—but the expression pattern and function of this gene were unknown. We therefore analyzed the expression patterns of TaEXPA9-A/B/D in D2 in response to different abiotic stresses and exogenous phytohormone treatments in different organs. The entire length of TaEXPA9-A/B/D was obtained, and green fluorescent labeling was used for subcellular localization analysis of TaEXPA9-A/B/D on onion epidermis. The 35S::TaEXPA9-A/B/D expression vector was constructed, and an overexpression transgenic Arabidopsis thaliana line was obtained to examine the effects of the homologs of this expansin on plant growth and low temperature stress resistance. ResultsThe results showed that TaEXPA9-A/B/D transcription significantly increased at 4°C low temperature stress, its expression level was higher in the roots, and TaEXPA9-A/B/D was localized to the cell wall. The roots were well-developed in the overexpression A. thaliana, and the growth-related markers and setting rate were better than in the wild-type. Recovery was stronger in the overexpression plants after frost stress. At 4°C low temperature stress, the antioxidant enzyme activity and osmoregulatory substance content in the TaEXPA9-A/B/D-overexpressing A. thaliana plants were significantly higher than in the wild-type plants, and the degree of membrane lipid peroxidation was lower. ConclusionsIn summary, TaEXPA9-A/B/D participates in the low-temperature stress response and may increase the scavenging of reactive oxygen species caused by low temperature stress through the protective enzyme system. Additionally, TaEXPA9-A/B/D can increase the levels of small molecular organic substances to resist osmotic stress caused by low temperature.