Journal of Plant Research最新文献

Plants defend themselves against herbivores by recognizing herbivore-derived elicitors and activating intracellular signaling. In Arabidopsis, the receptor-like kinase HAK1 recognizes the poly-saccharide elicitor (FrA) from Spodoptera litura larvae, leading to the expression of defense-related genes such as PDF1.2. During this process, the cytoplasmic kinase CRK2 phosphorylates PBL27, triggers the ERF13 expression via ethylene signaling and subsequently leads to PDF1.2 expression. Herein, we investigated four cytoplasmic kinases from the same receptor-like cytoplasmic kinase (RLCK) VII family as PBL27 that interacts with CRK2. Among them, PBL11, like PBL27, is phosphorylated by CRK2 and induces PDF1.2 expression but does not affect ERF13 expression. The weight gain of S. litura larvae on PBL11-deficient mutant plants was only slightly higher than that of wild-type plants, suggesting that PBL11 may function as a minor RLCK that supports the defense response.

Analysis of the sex expression in 10 'Lemon' (mmff) cucumber plants (Cucumis sativus L.), known to be andromonoecious, revealed that 3 plants produced female flowers with short ovaries, resembling bisexual flowers, after producing male and bisexual flowers. To investigate the heredity pattern governing these aberrant female flowers with short ovaries, F₁ hybrid plants (MmFf) were generated through a cross between 'Dokanari-sennari' (MMFF) and 'Lemon' (mmff), and #4 (mmff) and #45 (mmFF) were meticulously selected from a pool of 45 F₂ segregants. Analysis of the sex expression in both 10 F₅ plants (mmff) derived from the #4 (mmff) and 10 F₄ plants (mmFF) derived from the #45 (mmFF) revealed that 8-9 plants produced female flowers with short ovaries after producing male and bisexual flowers. Notably, no female flowers with short ovaries were produced in the plants carrying the M gene, such as 'Dokanari-sennari' (MMFF), 8 F₁ hybrid plants (MmFf), and the 29 F₂ segregants (M-F-,M-ff). Thus, female flowers with short ovaries may be produced in some 'Lemon' (mmff) cucumber plants and their progeny, particularly those carrying the mm genotype (CS-ACS2 genes with c.97G > T mutations), after the production of male and bisexual flowers. However, no clear genetic rules governing the occurrence of these female flowers with short ovaries were observed. This is the first report on trimonoecious cucumber plants displaying male flowers, bisexual flowers with short ovaries, and female flowers with short ovaries, all on the same plant, under the influence of the mm genotype (CS-ACS2 genes with c.97G > T mutations).

In this study, members of the BvDof transcription factor family were identified in the beet genome data (Beta vulgaris L.) Through systematic analysis, 22 BvDof family genes were found in the beet genome, and they were divided into nine groups by phylogenetic analysis. Fifteen members of the BvERF family were involved in the transition to rapid root tuber growth. There was a tandem replication during the generation of the Dof gene family in sugar beet. Bv1_zfms, Bv_ofna, Bv5_racn, and Bv6_augo may be involved in the regulation of secondary cambium development in the beet root tuber. Bv9_nood, Bv1_zfms, and Bv6_cdca may be related to the growth rate of root tubers. The results provide a reference for further elucidating the molecular mechanism of the BvDof transcription factor, which regulates the development of beet root tubers.

Lignin is a phenolic polymer that is a major source of biomass. Oxidative enzymes, such as laccase and peroxidase, are required for lignin polymerisation. Laccase is a member of the multicopper oxidase family and has a high amino acid sequence similarity with ascorbate oxidase. However, the process of functional differentiation between the two enzymes remains poorly understood. In this study, the common ancestry sequence of laccase and ascorbate oxidase (AncMCO) was predicted via phylogenetic reconstruction, and its in vivo effect on lignin biosynthesis in Arabidopsis thaliana was assessed. The estimated AncMCO sequence conserved key residues that coordinate with copper ions, implying that the electron transfer system is likely to be conserved in AncMCO. However, multiple insertions/deletions corresponding to protein surface structures have been found between laccase, ascorbate oxidase, and AncMCO. The overexpression of canonical laccase (AtLAC4) and ascorbate oxidase (AtAAO1) in A. thaliana resulted in notable increases of syringyl/guaiacyl lignin unit ratio in stems, whereas, in contrast, the overexpression of AncMCO did not show any detectable change in lignin deposition. Transcriptomic analysis revealed that the AtAAO1-overexpressing line exhibited significant changes in the expression of a wide range of cell wall biosynthesis genes. These results highlight the importance of the molecular evolution of multicopper oxidase, which drives lignin biosynthesis during plant evolution.

In the region of slightly acidic pH (рН 5.7), the manganese cluster in oxygen-evolving complex of photosystem II (PSII) is more resistant to exogenous reductants. The effect of such pH on the heat inactivation efficiency of the electron transport chain (O₂ evolution and 2,6-dichlorophenolindophenol reduction) in PSII membranes and thylakoid membranes was investigated. Under thylakoid membranes illumination accompanied by lumen acidification, their resistance to heat inactivation increases. In the presence of protonophores, the rate of heat inactivation increases, which seems to be associated not with the protonophore mechanism, but with structural and/or functional changes in membranes. In PSII membrane preparations, the efficiency of the oxygen evolution inhibition at pH 5.7 is also lower than at pH 6.5. The role of reactive oxygen species in thermal inactivation of photosynthetic membranes was investigated using a lipophilic cyclic hydroxylamine ESR spin probe.

We have previously suggested that in rice (Oryza sativa L.) leaves of different ages and N nutrition statuses, photosystems II and I (PSII and PSI, respectively) are regulated depending on N partitioning to Rubisco, which can determine the magnitude of unutilized light energy. The robustness of this mechanism was tested using Rubisco-antisense transgenic rice plants, in which reduced N partitioning to Rubisco markedly increases unutilized light energy. In wild-type plants, N partitioning to Rubisco tended to be smaller in the leaves at lower positions owing to leaf senescence. In the transgenic plants, N partitioning to Rubisco was generally smaller than in the wild-type plants and was relatively constant among leaf positions. The quantum efficiency of PSII [Y(II)] and quantum yield of non-photochemical quenching [Y(NPQ)] correlated positively and negatively, respectively, with N partitioning to Rubisco irrespective of leaf position or genotype. The oxidation levels of the reaction center chlorophyll of PSI (P700) [Y(ND)] negatively correlated with N partitioning to Rubisco. However, in mature and early senescent leaves of the transgenic plants, Y(ND) was markedly lower than expected from N partitioning to Rubisco. These results suggest that in the transgenic plants, the regulation depending on N partitioning to Rubisco is robust for PSII but fails for PSI in mature and early senescing leaves. In these leaves, the magnitudes of P700 oxidation were found to be less than expected from the Y(II) and Y(NPQ) values. The mechanistic reasons and physiological implications of these phenomena are discussed.

The widespread use of antibiotics in intensive animal husbandry, and the agricultural utilization of manure from such farms, imposes a significant burden on the environment. Consequently, the effects of antibiotics should be studied not only in animals and humans but also in all components of biocenoses and agrocenoses. In our study, we analyze the impact of four different concentrations of tetracycline present in soil (0, 5, 50, and 500 mg/kg of soil) on the growth and key photosynthesis parameters of pea seedlings: chlorophyll concentration, aminolevulinic acid concentration, aminolevulinic acid dehydrogenase activity, and ribulose bisphosphate carboxylase-oxygenase (RuBisCO) activity. At the lowest tetracycline concentration, chlorophyll content decreased by 13% compared to the control (0 tetracycline), while at the highest antibiotic concentration, it decreased by as much as 27%. Similarly, the decrease in aminolevulinic acid (a chlorophyll precursor) concentration was significant, amounting to 34%. However, the activity of the dehydrogenase enzyme, which consumes this precursor, decreased even more drastically by 51%, indicating significant disturbances in the light phase of photosynthesis. However, the activity of RuBisCO in pea plants subjected to tetracycline was even more severely affected, dropping by 58%, 69%, and 70% in soils with increasing concentrations of tetracycline. The reduction in enzyme activity could only partially be explained by a less pronounced decrease in the quantity of RuBisCO (large subunit) protein, which amounted to 6.5%, 11%, and 35% for tetracycline concentrations of 5, 50, and 500 mg/kg of soil, respectively.

Previous studies have determined that Chloroluma gonocarpa (Sapotaceae), is a species that has cryptic dioecy. This type of sexual system is characterized by flowers that are morphologically perfect (both sexual whorls are present) but functionally pistillate or staminate (in each type of flower one of the sexual whorls is non-functional). In C. gonocarpa the pistillate flowers present well-developed stigma, functional ovules, and staminodes, while the staminate flowers present a poorly developed stigma, collapsed ovules, and pollen-producing anthers. In angiosperms, the abortion of sexual organs can occur at different stages of development (from pre-meiosis to post-meiosis), that is why we conducted an anatomical analysis of both flower types at various developmental stages. Using light microscopy, we described the processes of sporogenesis and gametogenesis to establish when the staminate flowers lose their pistillate function. To achieve this, we collected, fixed, and processed the flowers following conventional anatomical techniques for observation under a light microscope. Our findings reveal that pollen development occurs only in staminate flowers, while ovule development begins in both types of flowers but ceases in staminate flowers due to post-meiosis abortion. In contrast, normal development continues in pistillate flowers. These results suggest that dioecy in C. gonocarpa may have arisen from a gynodioecious pathway.

Athyrium yokoscense is hypertolerant to cadmium (Cd) and can grow normally under a high Cd concentration despite Cd being a highly toxic heavy metal. To mitigate Cd stress in general plant species, Cd is promptly chelated with a thiol compound and is isolated into vacuoles. Generated active oxygen species (ROS) in the cytoplasm are removed by reduced glutathione. However, we found many differences in the countermeasures in A. yokoscense. Thiol compounds accumulated in the stele of the roots, although a long-term Cd exposure induced Cd accumulation in the aerial parts. Synchrotron radiation-based X-ray fluorescence (SR-XRF) analysis indicated that a large amount of Cd was localized in the cell walls of the roots. Overexpression of AyNramp5a, encoding a representative Fe and Mn transporter of A. yokoscense, increased both Cd uptake and Fe and Mn uptake in rice calli under the Cd exposure conditions. Organic acids are known to play a key role in reducing Cd availability to the plants by forming chelation and preventing its entry in free form into the roots. In A. yokoscense roots, Organic acids were abundantly detected. Investigating the chemical forms of the Cd molecules by X-ray absorption fine structure (XAFS) analysis detected many compounds with Cd-oxygen (Cd-O) binding in A. yokoscense roots, whereas in the aerial parts, the ratio of the compounds with Cd-sulfur (Cd-S) binding was increased. Together, our results imply that the strong Cd tolerance of A. yokoscense is an attribute of the following two mechanisms: Cd-O compound formation in the cell wall is a barrier to reduce Cd uptake into aerial parts. Thiol compounds in the region of root stele are involved in detoxication of Cd by formation of Cd-S compounds.