Pisum sativum (Pea)

Towards absolute quantification of protein genetic variants in Pisum sativum extracts

In recent years, several studies have used proteomics approaches to characterize genetic variant profiles of agricultural raw materials. In such studies, the challenge is the quantification of the individual protein variants. In this study a novel UPLC-PDA-MS method with absolute and label-free UV-based peptide quantification was applied to quantify the genetic variants of legumin, vicilin and albumins in pea extracts. The aim was to investigate the applicability of this method and to identify challenges in determining protein concentration from the measured peptide concentrations. Analysis of the protein mass balance showed significant losses of proteins in extraction (37%) and of peptides in further sample preparation (69%). The challenge in calculating the extractable individual protein concentrations was how to deal with these insoluble peptides. The quantification approach using average amino acid concentrations in each position of the sequence showed most reproducible results and allowed comparison of the genetic protein composition of 8 different cultivars. The extractable protein composition (μM/μM) was remarkably similar for all cultivar extracts and consisted of legumins A1 (12.8 ± 1.2%), A2 (1.1 ± 0.4%), B (9.9 ± 1.6%), J (7.5 ± 1.0%) and K (10.3 ± 2.1%), vicilin (15.2 ± 1.7%), provicilin (15.7 ± 2.5%), convicilin (9.8 ± 0.8%), albumin A1 (7.4 ± 2.0%), albumin 2 (10.0 ± 1.5%) and protease inhibitor (0.4 ± 0.4%).

Disease Resistance and Molecular Variations in Irradiation Induced Mutants of Two Pea Cultivars

Induced mutation is useful for improving the disease resistance of various crops. Fusarium wilt and powdery mildew are two important diseases which severely influence pea production worldwide. In this study, we first evaluated Fusarium wilt and powdery mildew resistance of mutants derived from two elite vegetable pea cultivars, Shijiadacaiwan 1 (SJ1) and Chengwan 8 (CW8), respectively. Nine SJ1 and five CW8 M3 mutants showed resistant variations in Fusarium wilt, and the same five CW8 mutants in powdery mildew. These resistant variations were confirmed in M4 and M5 mutants as well. Then, we investigated the genetic variations and relationships of mutant lines using simple sequence repeat (SSR) markers. Among the nine effective SSR markers, the genetic diversity index and polymorphism information content (PIC) values were averaged at 0.55 and 0.46, which revealed considerable genetic variations in the mutants. The phylogenetic tree and population structure analyses divided the M3 mutants into two major groups at 0.62 genetic similarity (K = 2), which clearly separated the mutants of the two cultivars and indicated that a great genetic difference existed between the two mutant populations. Further, the two genetic groups were divided into five subgroups at 0.86 genetic similarity (K = 5) and each subgroup associated with resistant phenotypes of the mutants. Finally, the homologous PsMLO1 cDNA of five CW8 mutants that gained resistance to powdery mildew was amplified and cloned. A 129 bp fragment deletion was found in the PsMLO1 gene, which was in accord with er1-2. The findings provide important information on disease resistant and molecular variations of pea mutants, which is useful for pea production, new cultivar breeding, and the identification of resistance genes.

The Newly Sequenced Genome of Pisum sativum Is Replete with Potential G-Quadruplex-Forming Sequences-Implications for Evolution and Biological Regulation

G-quadruplexes (G4s) have been long considered rare and physiologically unimportant in vitro curiosities, but recent methodological advances have proved their presence and functions in vivo. Moreover, in addition to their functional relevance in bacteria and animals, including humans, their importance has been recently demonstrated in evolutionarily distinct plant species. In this study, we analyzed the genome of Pisum sativum (garden pea, or the so-called green pea), a unique member of the Fabaceae family. Our results showed that this genome contained putative G4 sequences (PQSs). Interestingly, these PQSs were located nonrandomly in the nuclear genome. We also found PQSs in mitochondrial (mt) and chloroplast (cp) DNA, and we experimentally confirmed G4 formation for sequences found in these two organelles. The frequency of PQSs for nuclear DNA was 0.42 PQSs per thousand base pairs (kbp), in the same range as for cpDNA (0.53/kbp), but significantly lower than what was found for mitochondrial DNA (1.58/kbp). In the nuclear genome, PQSs were mainly associated with regulatory regions, including 5'UTRs, and upstream of the rRNA region. In contrast to genomic DNA, PQSs were located around RNA genes in cpDNA and mtDNA. Interestingly, PQSs were also associated with specific transposable elements such as TIR and LTR and around them, pointing to their role in their spreading in nuclear DNA. The nonrandom localization of PQSs uncovered their evolutionary and functional significance in the Pisum sativum genome.

Genome-wide identification of invertases in Fabaceae, focusing on transcriptional regulation of Pisum sativum invertases in seed subjected to drought

Invertases are key enzymes for carbon metabolism, cleaving sucrose into energy-rich and signaling metabolites, glucose and fructose. Invertases play pivotal roles in development and stress response, determining yield and quality of seed production. In this context, the repertoire of invertase gene families is critically scarce in legumes. Here, we performed a systematic search for invertase families in 16 Fabaceae genomes. For instance, we identified 19 invertase genes in the model plant Medicago and 17 accessions in the agronomic crop Pisum sativum. Our comprehensive phylogenetic analysis sets a milestone for the scientific community as we propose a new nomenclature to correctly name plant invertases. Thus, neutral invertases were classified into four clades of cytosolic invertase (CINV). Acid invertases were classified into two cell wall invertase clades (CWINV) and two vacuolar invertase clades (VINV). Then, we explored transcriptional regulation of the pea invertase family, focusing on seed development and water stress. Invertase expression decreased sharply from embryogenesis to seed-filling stages, consistent with higher sucrose and lower monosaccharide contents. The vacuolar invertase PsVINV1.1 clearly marked the transition between both developmental stages. We hypothesize that the predominantly expressed cell wall invertase, PsCWINV1.2, may drive sucrose unloading towards developing seeds. The same candidates, PsVINV1.1 and PsCWINV1.2, were also regulated by water deficit during embryonic stage. We suggest that PsVINV1.1 along with vacuolar sugar transporters maintain cellular osmotic pressure and PsCWINV1.2 control hexose provision, thereby ensuring embryo survival in drought conditions. Altogether, our findings provide novel insights into the regulation of plant carbon metabolism in a challenging environment.

The Combined Effect of ZnO and CeO2 Nanoparticles on Pisum sativum L.: A Photosynthesis and Nutrients Uptake Study

Cerium oxide nanoparticles (CeO2 NPs) and zinc oxide nanoparticles (ZnO NPs) are emerging pollutants that are likely to occur in the contemporary environment. So far, their combined effects on terrestrial plants have not been thoroughly investigated. Obviously, this subject is a challenge for modern ecotoxicology. In this study, Pisum sativum L. plants were exposed to either CeO2 NPs or ZnO NPs alone, or mixtures of these nano-oxides (at two concentrations: 100 and 200 mg/L). The plants were cultivated in hydroponic system for twelve days. The combined effect of NPs was proved by 1D ANOVA augmented by Tukey's post hoc test at p = 0.95. It affected all major plant growth and photosynthesis parameters. Additionally, HR-CS AAS and ICP-OES were used to determine concentrations of Cu, Mn, Fe, Mg, Ca, K, Zn, and Ce in roots and shoots. Treatment of the pea plants with the NPs, either alone or in combination affected the homeostasis of these metals in the plants. CeO2 NPs stimulated the photosynthesis rate, while ZnO NPs prompted stomatal and biochemical limitations. In the mixed ZnO and CeO2 treatments, the latter effects were decreased by CeO2 NPs. These results indicate that free radicals scavenging properties of CeO2 NPs mitigate the toxicity symptoms induced in the plants by ZnO NPs.