Journal of Plant Biochemistry and Biotechnology最新文献

Stevia plants are well-known for their ability to synthesize steviol glycosides (SGs), a natural sweetener blend. The principal SGs include stevioside (STV) and Rebaudioside-A (Reb-A), with the latter exhibiting superior sweetness and organoleptic properties. UDP glucosyltransferase-76G1 (UGT76G1) is responsible for converting STV to Reb-A, determining the intensity of sweetness. A better understanding of the structure/activity of SrUGT76G1 could provide insights into Reb-A production in stevia plants. To this end, a combination of enzymatic assays and sequencing analysis was performed using two stevia genotypes (Brazilian and Spanish) with contrasting Reb-A production capabilities (off/on). Relative expression of SrUGT76G1 gene showed remarkably higher expression (~ threefold) in Spanish samples compared to Brazilian ones. Foliar protein fractions (crude or partially purified extract) from Brazil plants were unable to convert STV into Reb-A under in vitro conditions, resulting in undetectable levels of Reb-A by HPLC. Molecular analyses revealed that the Brazilian SrUGT76G1 gene not only presents a premature stop codon, resulting in the absence of PSPG motif responsible for the binding of glycosyl groups, but also exhibits mutations affecting key amino acid residues in the acceptor-binding pocket. These alterations provide a plausible explanation for the Brazilian protein inability to catalyze the transformation of STV into Reb-A.

Graphical abstract

Zinc (Zn) biofortification of rice can address Zn malnutrition in Asia. Identification and introgression of QTLs for grain Zn content and yield (YLD) can improve the efficiency of rice Zn biofortification. In four rice populations we detected 56 QTLs for seven traits by inclusive composite interval mapping (ICIM), and 16 QTLs for two traits (YLD and Zn) by association mapping. The phenotypic variance (PV) varied from 4.5% (qPN_4.1) to 31.7% (qPH_1.1). qDF_1.1, qDF_7.2, qDF_8.1, qPH_1.1, qPH_7.1, qPL_1.2, qPL_9.1, qZn_5.1, qZn_5.2, qZn_6.1 and qZn_7.1 were identified in both dry and wet seasons; qZn_5.1, qZn_5.2, qZn_5.3, qZn_6.2, qZn_7.1 and qYLD_1.2 were detected by both ICIM and association mapping. qZn_7.1 had the highest PV (17.8%) and additive effect (2.5 ppm). Epistasis and QTL co-locations were also observed for different traits. The multi-trait genomic prediction values were 0.24 and 0.16 for YLD and Zn respectively. qZn_6.2 was co-located with a gene (OsHMA2) involved in Zn transport. These results are useful for Zn biofortificatiton of rice.

The ratio of oleic acid to linoleic acid (O/L) is crucial for determining the shelf life of peanut oil. In peanuts, the expression of the Fatty Acid Desaturase 2 (FAD2) enzyme, which converts oleic acid to linoleic acid, is regulated by two homeologous genes called AhFAD2A and AhFAD2B. It has been observed that the Indian peanut cultivar GG20 does not possess natural mutations in the AhFAD2B gene. We successfully introduced a construct called CRISPR_GG20_AhFAD2B into the de-embryonated cotyledon of the GG20 plant. The purpose of this construct was to utilize the CRISPR-Cas9 gene editing technology to modify the AhFAD2B gene. Genotyping analysis of the plants that were potentially transformed with the construct confirmed that the target-specific editing had occurred in the AhFAD2B gene. Subsequently, the edited GG20 plants were phenotypically evaluated to assess the fatty acid composition in the peanut kernels. The results showed a notable increase in the O/L ratio, which rose from 3.1 in the control to 7.3 in the edited GG20 plants. This implies that the gene editing technique successfully enhanced the oleic acid to linoleic acid ratio in the peanuts, potentially improving the shelf life of the resulting peanut oil.

Arsenate As(V), characterized as a metalloid with heavy metal properties, is prevalent in various environments. The consumption of food derived from plants contaminated with arsenate contributes significantly to human exposure to arsenic, posing potential health risks. However, the mechanisms governing plant responses to arsenate stress and the regulation of relevant transporter functions remain inadequately understood. Recently, Wang and co-workers, identified a calcium-dependent protein kinase, specifically CALCIUM-DEPENDENT PROTEIN KINASE 23 (CPK23), which shows interaction with the plasma membrane As(V)/Pi transporter PHOSPHATE TRANSPORTER 1;1 (PHT1;1) to channelize the Ca²⁺ signal in Arabidopsis roots under As(V) stress. The authors observed that cpk23 mutants showed increased sensitivity, whereas the overexpression of CPK23 resulted in enhanced tolerance under As(V) stress conferring role in As stress. Moreover, it has been demonstrated that CPK23 phosphorylates PHT1.1 at the Ser⁵¹⁴ (S⁵¹⁴) site is crucial for its function and proper localization under As(V) stress. Thus, this commentary offers valuable insights into the induction of a notable Ca²⁺ signal in Arabidopsis roots under As(V) stress that could guide crop bioengineering efforts aimed at addressing arsenate pollution in soil with targeted strategies.

Pigeonpea (Cajanus cajan L.) is an important source of quality dietary protein for over a billion people worldwide. The seeds of pigeonpea contain approximately 20–22% digestible protein, which makes it a valuable source of nutrition. Despite this, there has been little attention paid to enhancing the seed protein content (SPC) through genetic means. Recently, high-protein germplasm lines have been discovered in the secondary gene pool, which presents an opportunity to breed for high-protein cultivars. To accelerate the breeding process, genomics-assisted breeding (GAB) can be utilized. In this context, this study identified the superior haplotypes for the genes that control SPC in pigeonpea. Whole-genome re-sequencing (WGRS) data from 344 pigeonpea genotypes were analyzed to identify the superior haplotypes for 57 SPC governing genes. A total of 231 haplotypes in 43 candidate genes were identified, and haplo-pheno analysis was performed to provide superior haplotypes for 10 genes. The identification of superior haplotypes and genotypes will greatly facilitate the development of protein-rich pigeonpea seeds through the application of haplotype-based breeding (HBB).

Due to the resistance of Artemia urmiana to salt stress, researchers have isolated and investigated Artemin, the most prevalent protein within the cyst of this aquatic species. In vitro studies have revealed Artemin's role as a molecular chaperone, effectively engaging with the hydrophobic surfaces of unfolded and/or partially folded proteins. In light of Artemin's established functional significance, its encoding gene has been successfully introduced into mammalian cells; however, no published research has elucidated its potential role within plant cells. In the current investigation, the artemin gene was successfully cloned into the pPZPY122 plant vector and subsequently introduced into Arabidopsis thaliana plants. The T₃ homozygote transgenic plants (art) were then subjected to a series of environmental stresses, including heat, salt (NaCl) and drought (Mannitol). To assess the mutant's resilience to these stresses, their seed germination indices were evaluated. The art line demonstrated a higher degree of tolerance towards the abiotic stresses. A comparative analysis revealed that ascorbate peroxidase activity, catalase activity, and proline content exhibited significantly enhanced levels in some NaCl-treated art plants compared to their counterparts in Col-0. Regarding the expression of the genes in the SOS pathway, it was found that SOS1 is significantly upregulated under NaCl treatment in the art mutant. Conversely, under normal growth conditions, the morphology and growth of transgenics remained indistinguishable from those of wild-type plants.

Groundnut is a rich source of several nutritional components including polyphenols and antioxidants that offer various health benefits. In this regard, the mini core accessions along with elite varieties of groundnut were used to assess genetic diversity using AhTE markers. The phenotypic observation on eight morphological, six productivity and two nutraceutical traits [total polyphenol content (TPC) and total antioxidant activity (AOA)] were studied. Correlation studies revealed a significant positive correlation between TPC and AOA. The degree of divergence with respect to nutraceutical content among the genotypes of mini core collection and elite cultivars is evident from the current study. The STRUCTURE analyses revealed the grouping of genotypes into three distinct clusters mainly based on the botanical types of groundnut. The analysis of molecular variance displayed maximum variation (97%) within the individuals of subpopulations and minimum variation (3%) among subpopulations. Principal component analysis exhibited 3 principal components that accounted for 42.17% of the total variation. Association mapping study indicated 20 significant marker-trait associations at 1% probability. The study has also identified significant marker-trait associations with nutraceutical properties of groundnut, AhTE0465-TPC and AhTE0381- AOA with explained phenotypic variation of 7.45% and 6.85% respectively. These markers were found to have positions at A02 and A09 with bHLH DNA-binding family protein and chitinase putative functions respectively. The markers associated with TPC and AOA can further be utilized for genomics-assisted breeding for nutritionally rich cultivars in groundnut.

Proteins in endosperms of mature wheat seeds contain ~ 2.5% lysine. Proteins in endosperms of immature wheat seeds after 8 days of anthesis, interestingly contain ~ 8% lysine. Wheat endosperm proteins collected 15 days after anthesis, when treated with proteases isolated from endosperms 20 days after anthesis, released 10.2% lysine and 5.6% leucine. In contrast, the same proteins, when treated with proteases isolated from endosperms 8 days after anthesis, released 7.0% lysine and 12.0% leucine. The protease C, that could cleave polylysine, but could not cleave polyaspartic acid and polyglutamic acid, appeared only at 16 days after anthesis and continued to be present till 28 days after anthesis. Soybean trypsin inhibitor inhibited the activity of protease C completely. Transcriptome analysis of developing wheat seeds has revealed the presence of three major transcripts containing trypsin-like domains. The amounts of these three transcripts increased from 2 weeks after anthesis to 4 weeks after anthesis and decreased thereafter. If a wheat variety could be created which is devoid of protease C or the above mentioned trypsin like proteases, the lysine content of endosperm proteins of that variety would possibly be higher. This could today be achieved by using the CRISPR-Cas systems of genome editing.

Tulsi (Holi Basil, Ocimum tenuiflorum) is extensively used in herbal medicine, and it includes two distinct subtypes; namely green Tulsi and purple Tulsi. Both types have similar medicinal properties. However, purple Tulsi contains a significantly higher amount of methyleugenol, which is genotoxic, and its daily intake is restricted. We developed a polymerase chain reaction-restriction fragment length polymorphism (PCR–RFLP) method to identify purple Tulsi. For this purpose, we selected a C > T single nucleotide polymorphism (SNP) in the ycf1 gene of the chloroplast genome that overlapped with a DdeI restriction site. The primers and PCR conditions were optimized to amplify a 797 bp DNA encompassing the C > T SNP, specifically from O. tenuiflorum. After restriction digestion of the PCR product with DdeI, green Tulsi was identified by two fragments (539 bp and 258 bp), and purple Tulsi was recognized by a single fragment (797 bp). Analysis of 40 Tulsi market samples revealed that only 36 (90%) were derived from O. tenuiflorum. The majority of the market samples were purple Tulsi (60%) or a mixture of green and purple Tulsi (27.5%), with some mixed samples containing up to 50% purple Tulsi.

Abstract

The increasing global population projected to reach 9.7 billion by 2050 from the current 7.7 billion, which is going to significantly impact food availability. Therefore, current global agricultural production needs to be increased to feed the unconstrained growing population. The changing climatic condition due to anthropogenic activities also makes the conditions more challenging to meet the required crop productivity in the future. Potato is third most consumed staple food. The current cultivation and demand of potato is particularly more in developing countries with high levels of poverty, hunger, and malnutrition because it is cheap source of nutrition and easily available. Potato is severely infected by a number of diseases, insect pests, and abiotic environmental conditions. Amidst the backdrop of climate change, the situation is deteriorating. Projections indicate that the average potato productivity in India's primary potato-growing states, responsible for approximately 90% of the nation's total potato output, is expected to decline by 2.0% in the 2050s and a more substantial 6.4% in the 2080s. Therefore to develop tolerance in plants to cope with changing environmental condition is need of hour to feed the overgrowing population. In this review, we discussed the application of CRISPR to enhance the crop productivity and develop biotic and abiotic stress-tolerant in potato to face the current changing climatic conditions is also discussed. The review also sheds light on the future prospects of CRISPR/Cas technology for potato breeding, including potential challenges and opportunities.