Proteomic analysis of salt-stressed tomato (Solanum lycopersicum) seedlings: effect of genotype and exogenous application of glycinebetaine

An investigation aimed at a better understanding of the molecular adaptation mechanisms of salt stress was carried out in 7-d-old tomato Solanum lycopersicum (L.) Mill cultivars Patio and ‘F144’, using a proteomic approach. Total proteins were extracted from radicles and hypocotyls collected from both non-saline control and salt-stressed seedlings, and separated by two-dimensional gel electrophoresis. Liqud chromatography-electron spray ionization tandem mass spectrometry (LC-ESI-MS/MS) identified 23 salt stress response proteins, classified into six functional categories. The effect of exogenously applied glycinebetaine (GB) on the salt stress-induced inhibition of growth in tomato seedlings of cultivars Patio and ‘F144’ and on the protein profile was investigated. It was found that GB could alleviate the inhibition of tomato growth induced by salt stress through changing the expression abundance of six proteins in Patio and two proteins in ‘F144’ more than twice compared with salt-stressed seedlings. Furthermore, the interaction analysis based on computational bioinformatics reveals major regulating networks: photosystem II (PSII), Rubisco, and superoxide dismutase (SOD). The results suggest that it is likely that improvement of salt tolerance in tomato might be achieved through the application of exogenous compatible solutes, such as GB. Moreover, quantitative and qualitative analysis of the differentially expressed proteins of tomato under salt stress is an important step towards further elucidation of mechanisms of salt stress resistance

Storage Root of Cassava: Morphological Types, Anatomy, Formation, Growth, Development and Harvest Time

Cassava (Manihot esculenta, Crantz) is considered a starchy root crop that provides staple food for millions of people in tropical and subtropical regions of the world. Research efforts are directed toward genetic breeding and cultivation of cassava to improve cassava storage root starch production, nutritional values, and industrial utilization. Cassava storage root (CSR) is a vegetative storage organ with indeterminate type of growth that has a central cylinder (edible part) originated by the swelling of primary root and crown roots. Comprehensive studies on thickened primary root (secondary growth) are rare, incomplete, and to a certain extent, missing. In this chapter, we review and forward studies that move our knowledge on cassava storage root (CSR). CSR generally forms up to 12–14 storage root (SR) per plant, which can originate from three sources of propagating plant materials as well as being induced in vivo and in vitro. Types of storage root (morphologically defined), CSR physiology, tissue anatomy/histology (secondary growth), chemical composition of the edible part, biochemical features, gene expression and proteomics as secondary growth proceeds are of major importance in order to breed cassava plant for agriculture utilization. Storage root morphology varies in shape from cylindrical to globular. Time to initiation of storage root formation varies from 45 to 90 days after planting (DAP), depending on the leaf auxiliary bud position in the vegetative propagating material at the plant source. Storage root growth, starch accumulation, and nutrient contents are largely dependent on genotypes. Storage root anatomy can be identified by eight characteristics common to a root with secondary growth and starch reserve variants. Histological characterizations can be used to identify cell types of primary and secondary meristems, procambium, vascular cambium, phellogen, phelloderm, primary and secondary xylem and phloem, storage parenchyma and sclerenchyma. Three types of meristematic cell differentiations occur as secondary growth proceeds; one due to cork cambium with plane perpendicularly oriented cell division, second due to plane longitudinally oriented cell division in the root apex, and third longitudinally oriented in the epidermal cells. Chemical composition of the storage root varies in the central cylinder (edible part) depending on the sample position in the root and the plant genotype. Therefore, biochemical characteristics are known to change with tissue age as secondary growth proceeds. Moreover, the composition of stored starch varies with tissue age across the central cylinder and may be used as a physiological indicator for bulk storage root maturation and storage root harvest time

Domestication Syndrome in Cassava (Manihot esculenta Crantz): Assessing Morphological Traits and Differentially Expressed Genes Associated with Genetic Diversity of Storage Root

Cassava (Manihot esculenta Crantz) provides a staple food source for millions of people in tropical and subtropical world regions. Brazil is the major center of diversification for species of the Manihot, and a center for domestication of the cultivated species originated from wild ancestral M. esculenta subsp. flabellifolia. Genetic breeding of cassava depends on landraces. Molecular phylogenetic technologies used to study genetic traits selected by mankind in crops, are likely to predict proposed “domestication syndrome.” Phylogenetic trees use DNA sequences alignment to infer on gene historical events. A study on regulatory and structural complexity that dictates gene/protein function, will add non-sequence information to predict a more complete understanding of functional evolution. Transcriptional profile contains critical information on when and where a gene is manifested. These regulatory properties could explain functional genes diversity achieved within gene families across closely related species such as cassava and its ancestor. Microarray technologies measure transcriptional response of gene to a given environmental or genetic factor. Integration of genomic and transcriptomic data provides more detailed picture of molecular evolution. This chapter describes comprehensive study using the wild relative of cassava ancestor, recognition of natural morphological trait changes during domestication, and gene expression of cassava storage root

The analysis of candidate genes and loci involved with carotenoid metabolism in cassava (Manihot esculenta Crantz) using SLAF-seq

Carotenoids in cassava storage roots play important roles in benefiting people’s health in the tropics because they provide essential nutrients and antioxidants. Although the related genes and loci associated with carotenoid metabolism in many species are well reported, in cassava they are poorly understood. In the present study, GWAS base on SLAF-seq was used in detecting the related genes and loci correlated to carotenoid contents in 98 accessions from a cassava F1 mapping population. The 98 accessions were divided into four subgroups. On the basis of general linear and compressed linear models, 144 genes were detected by selective sweep analysis, and 84 SNPs and 694 genes were detected by association mapping, in which Manes.04G164700 (XanDH) and Manes.11G105300 (AAO) were probably involved in the downstream pathway of carotenoid metabolism, and their expressions in six cassava genotypes were confirmed. Our results will be useful in yellow-root cassava variety improvement and provide the most effective and sustainable approach to maximize the nutritional and health benefits of carotenoid to a large number of populations

Proteome characterization of cassava (Manihot esculenta Crantz) somatic embryos, plantlets and tuberous roots

<p>Abstract</p> <p>Background</p> <p>Proteomics is increasingly becoming an important tool for the study of many different aspects of plant functions, such as investigating the molecular processes underlying in plant physiology, development, differentiation and their interaction with the environments. To investigate the cassava (<it>Manihot esculenta </it>Crantz) proteome, we extracted proteins from somatic embryos, plantlets and tuberous roots of cultivar SC8 and separated them by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE).</p> <p>Results</p> <p>Analysis by liquid chromatography-electrospray ionisation-tandem mass spectrometry (LC-ESI-MS/MS) yielded a total of 383 proteins including isoforms, classified into 14 functional groups. The majority of these were carbohydrate and energy metabolism associated proteins (27.2%), followed by those involved in protein biosynthesis (14.4%). Subsequent analysis has revealed that 54, 59, 74 and 102 identified proteins are unique to the somatic embryos, shoots, adventitious roots and tuberous roots, respectively. Some of these proteins may serve as signatures for the physiological and developmental stages of somatic embryos, shoots, adventitious roots and tuberous root. Western blotting results have shown high expression levels of Rubisco in shoots and its absence in the somatic embryos. In addition, high-level expression of α-tubulin was found in tuberous roots, and a low-level one in somatic embryos. This extensive study effectively provides a huge data set of dynamic protein-related information to better understand the molecular basis underlying cassava growth, development, and physiological functions.</p> <p>Conclusion</p> <p>This work paves the way towards a comprehensive, system-wide analysis of the cassava. Integration with transcriptomics, metabolomics and other large scale "-omics" data with systems biology approaches can open new avenues towards engineering cassava to enhance yields, improve nutritional value and overcome the problem of post-harvest physiological deterioration.</p

編集後記

千葉医学雑誌57-

Domestication syndrome is investigated by proteomic analysis between cultivated cassava (Manihot esculenta Crantz) and its wild relatives

Cassava (Manihot esculenta Crantz) wild relatives remain a largely untapped potential for genetic improvement. However, the domestication syndrome phenomena from wild species to cultivated cassava remain poorly understood. The analysis of leaf anatomy and photosynthetic activity showed significantly different between cassava cultivars SC205, SC8 and wild relative M. esculenta ssp. Flabellifolia (W14). The dry matter, starch and amylose contents in the storage roots of cassava cultivars were significantly more than that in wild species. In order to further reveal the differences in photosynthesis and starch accumulation of cultivars and wild species, the globally differential proteins between cassava SC205, SC8 and W14 were analyzed using 2-DE in combination with MALDI-TOF tandem mass spectrometry. A total of 175 and 304 proteins in leaves and storage roots were identified, respectively. Of these, 122 and 127 common proteins in leaves and storage roots were detected in SC205, SC8 and W14, respectively. There were 11, 2 and 2 unique proteins in leaves, as well as 58, 9 and 12 unique proteins in storage roots for W14, SC205 and SC8, respectively, indicating proteomic changes in leaves and storage roots between cultivated cassava and its wild relatives. These proteins and their differential regulation across plants of contrasting leaf morphology, leaf anatomy pattern and photosynthetic related parameters and starch content could contribute to the footprinting of cassava domestication syndrome. We conclude that these global protein data would be of great value to detect the key gene groups related to cassava selection in the domestication syndrome phenomena

Cassava genome from a wild ancestor to cultivated varieties

Cassava is a major tropical food crop in the Euphorbiaceae family that has high carbohydrate production potential and adaptability to diverse environments. Here we present the draft genome sequences of a wild ancestor and a domesticated variety of cassava and comparative analyses with a partial inbred line. We identify 1,584 and 1,678 gene models specific to the wild and domesticated varieties, respectively, and discover high heterozygosity and millions of single-nucleotide variations. Our analyses reveal that genes involved in photosynthesis, starch accumulation and abiotic stresses have been positively selected, whereas those involved in cell wall biosynthesis and secondary metabolism, including cyanogenic glucoside formation, have been negatively selected in the cultivated varieties, reflecting the result of natural selection and domestication. Differences in microRNA genes and retrotransposon regulation could partly explain an increased carbon flux towards starch accumulation and reduced cyanogenic glucoside accumulation in domesticated cassava. These results may contribute to genetic improvement of cassava through better understanding of its biology