Bradyrhizobium ottawaense efficiently reduces nitrous oxide through high nosZ gene expression.

N2O is an important greenhouse gas influencing global warming, and agricultural land is the predominant (anthropogenic) source of N2O emissions. Here, we report the high N2O-reducing activity of Bradyrhizobium ottawaense, suggesting the potential for efficiently mitigating N2O emission from agricultural lands. Among the 15 B. ottawaense isolates examined, the N2O-reducing activities of most (13) strains were approximately five-fold higher than that of Bradyrhizobium diazoefficiens USDA110T under anaerobic conditions. This robust N2O-reducing activity of B. ottawaense was confirmed by N2O reductase (NosZ) protein levels and by mitigation of N2O emitted by nodule decomposition in laboratory system. While the NosZ of B. ottawaense and B. diazoefficiens showed high homology, nosZ gene expression in B. ottawaense was over 150-fold higher than that in B. diazoefficiens USDA110T, suggesting the high N2O-reducing activity of B. ottawaense is achieved by high nos expression. Furthermore, we examined the nos operon transcription start sites and found that, unlike B. diazoefficiens, B. ottawaense has two transcription start sites under N2O-respiring conditions, which may contribute to the high nosZ expression. Our study indicates the potential of B. ottawaense for effective N2O reduction and unique regulation of nos gene expression towards the high performance of N2O mitigation in the soil.

Deciphering transcriptomic signatures explaining the phenotypic plasticity of nonheading lettuce genotypes under artificial light conditions.

Elucidating the mechanisms and pathways involved in genotype-environment (G×E) interactions and phenotypic plasticity is critical for improving plant growth. Controlled environment agricultural systems allow growers to modulate the environment for particular genotypes. In this study, we evaluated the effects of interactions among 14 genotypes and four artificial light environments on leaf lettuce phenotypes and dissected the underlying molecular mechanism via transcriptome-based modeling. Variations in morphological traits and phytochemical concentrations in response to artificial light treatments revealed significant G×E interactions. The appropriate genotype and artificial light combinations for maximizing phenotypic expression were determined on the basis of a joint regression analysis and the additive main effect and multiplicative interaction model for these G×E interactions. Transcriptome-based regression modeling explained approximately 50%-90% of the G×E variations. Further analyzes indicated Red Lettuce Leaves 4 (RLL4) regulates UV-B and blue light signaling through the effects of the HY5-MBW pathway on flavonoid biosynthesis and contributes to natural variations in the light-responsive plasticity of lettuce traits. Our study represents an important step toward elucidating the phenotypic variations due to G×E interactions in nonheading lettuce under artificial light conditions.

Cell-surface protein YwfG of Lactococcus lactis binds to α-1,2-linked mannose.

Lactococcus lactis strains are used as starter cultures in the production of fermented dairy and vegetable foods, but the species also occurs in other niches such as plant material. Lactococcus lactis subsp. lactis G50 (G50) is a plant-derived strain and potential candidate probiotics. Western blotting of cell-wall proteins using antibodies generated against whole G50 cells detected a 120-kDa protein. MALDI-TOF MS analysis identified it as YwfG, a Leu-Pro-any-Thr-Gly cell-wall-anchor-domain-containing protein. Based on a predicted domain structure, a recombinant YwfG variant covering the N-terminal half (aa 28-511) of YwfG (YwfG28-511) was crystallized and the crystal structure was determined. The structure consisted of an L-type lectin domain, a mucin-binding protein domain, and a mucus-binding protein repeat. Recombinant YwfG variants containing combinations of these domains (YwfG28-270, YwfG28-336, YwfG28-511, MubR4) were prepared and their interactions with monosaccharides were examined by isothermal titration calorimetry; the only interaction observed was between YwfG28-270, which contained the L-type lectin domain, and d-mannose. Among four mannobioses, α-1,2-mannobiose had the highest affinity for YwfG28-270 (dissociation constant = 34 µM). YwfG28-270 also interacted with yeast mannoproteins and yeast mannan. Soaking of the crystals of YwfG28-511 with mannose or α-1,2-mannobiose revealed that both sugars bound to the L-type lectin domain in a similar manner, although the presence of the mucin-binding protein domain and the mucus-binding protein repeat within the recombinant protein inhibited the interaction between the L-type lectin domain and mannose residues. Three of the YwfG variants (except MubR4) induced aggregation of yeast cells. Strain G50 also induced aggregation of yeast cells, which was abolished by deletion of ywfG from G50, suggesting that surface YwfG contributes to the interaction with yeast cells. These findings provide new structural and functional insights into the interaction between L. lactis and its ecological niche via binding of the cell-surface protein YwfG with mannose.

Processing of D1 Protein: A Mysterious Process Carried Out in Thylakoid Lumen.

In oxygenic photosynthetic organisms, D1 protein, a core subunit of photosystem II (PSII), displays a rapid turnover in the light, in which D1 proteins are distinctively damaged and immediately removed from the PSII. In parallel, as a repair process, D1 proteins are synthesized and simultaneously assembled into the PSII. On this flow, the D1 protein is synthesized as a precursor with a carboxyl-terminal extension, and the D1 processing is defined as a step for proteolytic removal of the extension by a specific protease, CtpA. The D1 processing plays a crucial role in appearance of water-oxidizing capacity of PSII, because the main chain carboxyl group at carboxyl-terminus of the D1 protein, exposed by the D1 processing, ligates a manganese and a calcium atom in the Mn4CaO5-cluster, a special equipment for water-oxidizing chemistry of PSII. This review focuses on the D1 processing and discusses it from four angles: (i) Discovery of the D1 processing and recognition of its importance: (ii) Enzyme involved in the D1 processing: (iii) Efforts for understanding significance of the D1 processing: (iv) Remaining mysteries in the D1 processing. Through the review, I summarize the current status of our knowledge on and around the D1 processing.

Genetic effects of Red Lettuce Leaf genes on red coloration in leaf lettuce under artificial lighting conditions.

Some cultivars of lettuce accumulate anthocyanins, which act as functional food ingredients. Leaf lettuce has been known to be erratic in exhibiting red color when grown under artificial light, and there is a need for cultivars that more stably exhibit red color in artificial light cultivation. In this study, we aimed to dissect the genetic architecture for red coloring in various leaf lettuce cultivars grown under artificial light. We investigated the genotype of Red Lettuce Leaf (RLL) genes in 133 leaf lettuce strains, some of which were obtained from publicly available resequencing data. By studying the allelic combination of RLL genes, we further analyzed the contribution of these genes to producing red coloring in leaf lettuce. From the quantification of phenolic compounds and corresponding transcriptome data, we revealed that gene expression level-dependent regulation of RLL1 (bHLH) and RLL2 (MYB) is the underlying mechanism conferring high anthocyanin accumulation in red leaf lettuce under artificial light cultivation. Our data suggest that different combinations of RLL genotypes cause quantitative differences in anthocyanin accumulation among cultivars, and some genotype combinations are more effective at producing red coloration even under artificial lighting.

A Rice Ancestral Genetic Resource Conferring Ideal Plant Shapes for Vegetative Growth and Weed Suppression.

To maximize crop growth, crops need to capture sunlight efficiently. This property is primarily influenced by the shape of the crops such as the angle, area, and arrangement of leaves. We constructed a rice (Oryza sativa L.) inbred line that displayed an ideal transition of plant shapes in terms of sunlight receiving efficiency. During vegetative growth, this line exhibited tiller spreading with increased tiller number, which formed a parabolic antenna-like structure. The architecture probably improved light reception efficiency of individuals compared with the recurrent parent. The line achieved not only acceleration of the vegetative growth, but also significant suppression of weed growth under the canopy. The increased light reception efficiency of the line has consequently reduced the amount of incident light to the ground and supplied significant competitiveness against weeds. The spread tillers became erect from the entry of the reproductive growth phase, adaptively sustaining light reception efficiency in thicker stands. The line carries a small chromosomal segment from Oryza rufipogon Griff., a putative progenitor of Asian cultivated rice. The introduced chromosome segment had little effect on grain yield and quality. Our results shed light on potentials hidden in the wild rice chromosome segment to achieve the valuable traits.

The rhizobial autotransporter determines the symbiotic nitrogen fixation activity of Lotus japonicus in a host-specific manner.

Leguminous plants establish endosymbiotic associations with rhizobia and form root nodules in which the rhizobia fix atmospheric nitrogen. The host plant and intracellular rhizobia strictly control this symbiotic nitrogen fixation. We recently reported a Lotus japonicus Fix- mutant, apn1 (aspartic peptidase nodule-induced 1), that impairs symbiotic nitrogen fixation. APN1 encodes a nodule-specific aspartic peptidase involved in the Fix- phenotype in a rhizobial strain-specific manner. This host-strain specificity implies that some molecular interactions between host plant APN1 and rhizobial factors are required, although the biological function of APN1 in nodules and the mechanisms governing the interactions are unknown. To clarify how rhizobial factors are involved in strain-specific nitrogen fixation, we explored transposon mutants of Mesorhizobium loti strain TONO, which normally form Fix- nodules on apn1 roots, and identified TONO mutants that formed Fix+ nodules on apn1 The identified causal gene encodes an autotransporter, part of a protein secretion system of Gram-negative bacteria. Expression of the autotransporter gene in M. loti strain MAFF3030399, which normally forms Fix+ nodules on apn1 roots, resulted in Fix- nodules. The autotransporter of TONO functions to secrete a part of its own protein (a passenger domain) into extracellular spaces, and the recombinant APN1 protein cleaved the passenger protein in vitro. The M. loti autotransporter showed the activity to induce the genes involved in nodule senescence in a dose-dependent manner. Therefore, we conclude that the nodule-specific aspartic peptidase, APN1, suppresses negative effects of the rhizobial autotransporter in order to maintain effective symbiotic nitrogen fixation in root nodules.

A new buckwheat dihydroflavonol 4-reductase (DFR), with a unique substrate binding structure, has altered substrate specificity.

BACKGROUND: Dihydroflavonol 4-reductase (DFR) is the key enzyme committed to anthocyanin and proanthocyanidin biosynthesis in the flavonoid biosynthetic pathway. DFR proteins can catalyse mainly the three substrates (dihydrokaempferol, dihydroquercetin, and dihydromyricetin), and show different substrate preferences. Although relationships between the substrate preference and amino acids in the region responsible for substrate specificity have been investigated in several plant species, the molecular basis of the substrate preference of DFR is not yet fully understood. RESULTS: By using degenerate primers in a PCR, we isolated two cDNA clones that encoded DFR in buckwheat (Fagopyrum esculentum). Based on sequence similarity, one cDNA clone (FeDFR1a) was identical to the FeDFR in DNA databases (DDBJ/Gen Bank/EMBL). The other cDNA clone, FeDFR2, had a similar sequence to FeDFR1a, but a different exon-intron structure. Linkage analysis in an F2 segregating population showed that the two loci were linked. Unlike common DFR proteins in other plant species, FeDFR2 contained a valine instead of the typical asparagine at the third position and an extra glycine between sites 6 and 7 in the region that determines substrate specificity, and showed less activity against dihydrokaempferol than did FeDFR1a with an asparagine at the third position. Our 3D model suggested that the third residue and its neighbouring residues contribute to substrate specificity. FeDFR1a was expressed in all organs that we investigated, whereas FeDFR2 was preferentially expressed in roots and seeds. CONCLUSIONS: We isolated two buckwheat cDNA clones of DFR genes. FeDFR2 has unique structural and functional features that differ from those of previously reported DFRs in other plants. The 3D model suggested that not only the amino acid at the third position but also its neighbouring residues that are involved in the formation of the substrate-binding pocket play important roles in determining substrate preferences. The unique characteristics of FeDFR2 would provide a useful tool for future studies on the substrate specificity and organ-specific expression of DFRs.

Phytochrome B Mediates the Regulation of Chlorophyll Biosynthesis through Transcriptional Regulation of ChlH and GUN4 in Rice Seedlings.

Accurate regulation of chlorophyll synthesis is crucial for chloroplast formation during the greening process in angiosperms. In this study, we examined the role of phytochrome B (phyB) in the regulation of chlorophyll synthesis in rice seedlings (Oryza sativa L.) through the characterization of a pale-green phenotype observed in the phyB mutant grown under continuous red light (Rc) irradiation. Our results show that the Rc-induced chlorophyll accumulation can be divided into two components--a phyB-dependent and a phyB-independent component, and that the pale-green phenotype is caused by the absence of the phyB-dependent component. To elucidate the role of the missing component we established an Rc-induced greening experiment, the results of which revealed that several genes encoding proteins on the chlorophyll branch were repressed in the phyB mutant. Notable among them were ChlH and GUN4 genes, which encode subunit H and an activating factor of magnesium chelatase (Mg-chelatase), respectively, that were largely repressed in the mutant. Moreover, the kinetic profiles of chlorophyll precursors suggested that Mg-chelatase activity simultaneously decreased with the reduction in the transcript levels of ChlH and GUN4. These results suggest that phyB mediates the regulation of chlorophyll synthesis through transcriptional regulation of these two genes, whose products exert their action at the branching point of the chlorophyll biosynthesis pathway. Reduction of 5-aminolevulinic acid (5-ALA) synthesis could be detected in the mutant, but the kinetic profiles of chlorophyll precursors indicated that it was an event posterior to the reduction of the Mg-chelatase activity. It means that the repression of 5-ALA synthesis should not be a triggering event for the appearance of the pale-green phenotype. Instead, the repression of 5-ALA synthesis might be important for the subsequent stabilization of the pale-green phenotype for preventing excessive accumulation of hazardous chlorophyll precursors, which is an inevitable consequence of the reduction of Mg-chelatase activity.

Differences and similarities in the photoregulation of gibberellin metabolism between rice and dicots.

In rice seedlings, elongation of leaf sheaths is suppressed by light stimuli. The response is mediated by two classes of photoreceptors, phytochromes and cryptochromes. However, it remains unclear how these photoreceptors interact in the process. Our recent study using phytochrome mutants and novel cryptochrome RNAi lines revealed that cryptochromes and phytochromes function cooperatively, but independently to reduce active GA contents in seedlings in visible light. Blue light captured by cryptochrome 1 (cry1a and cry1b) induces robust expression of GA 2-oxidase genes (OsGA2ox4-7). In parallel, phytochrome B with auxiliary action of phytochrome A mediates repression of GA 20-oxidase genes (OsGA20ox2 and OsGA20ox4). The independent effects cumulatively reduce active GA contents, leading to a suppression of leaf sheath elongation. These regulatory mechanisms are distinct from phytochrome B function in dicots. We discuss reasons why the distinct system appeared in rice, and advantages of the rice system in early photomorphogenesis.

Cryptochrome and phytochrome cooperatively but independently reduce active gibberellin content in rice seedlings under light irradiation.

In contrast to a wealth of knowledge about the photoregulation of gibberellin metabolism in dicots, that in monocots remains largely unclear. In this study, we found that a blue light signal triggers reduction of active gibberellin content in rice seedlings with simultaneous repression of two gibberellin 20-oxidase genes (OsGA20ox2 and OsGA20ox4) and acute induction of four gibberellin 2-oxidase genes (OsGA2ox4-OsGA2ox7). For further examination of the regulation of these genes, we established a series of cryptochrome-deficient lines through reverse genetic screening from a Tos17 mutant population and construction of knockdown lines based on an RNA interference technique. By using these lines and phytochrome mutants, we elucidated that cryptochrome 1 (cry1), consisting of two species in rice plants (cry1a and cry1b), is indispensable for robust induction of the GA2ox genes. On the other hand, repression of the GA20ox genes is mediated by phytochromes. In addition, we found that the phytochromes also mediate the repression of a gibberellin 3-oxidase gene (OsGA3ox2) in the light. These results imply that, in rice seedlings, phytochromes mediate the repression of gibberellin biosynthesis capacity, while cry1 mediates the induction of gibberellin inactivation capacity. The cry1 action was demonstrated to be dominant in the reduction of active gibberellin content, but, in rice seedlings, the cumulative effects of these independent actions reduced active gibberellin content in the light. This pathway design in which different types of photoreceptors independently but cooperatively regulate active gibberellin content is unique from the viewpoint of dicot research. This redundancy should provide robustness to the response in rice plants.

Phytochrome-mediated growth inhibition of seminal roots in rice seedlings.

In rice (Oryza sativa) seedlings, continuous white-light irradiation inhibited the growth of seminal roots but promoted the growth of crown roots. In this study, we examined the mechanisms of photoinhibition of seminal root growth. Photoinhibition occurred in the absence of nitrogen but increased with increasing nitrogen concentrations. In the presence of nitrogen, photoinhibition was correlated with coiling of the root tips. The seminal roots were most photosensitive 48-72 h after germination during the 7-day period after germination. White-light irradiation for at least 6 h was required for photoinhibition, and the Bunsen-Roscoe law of reciprocity was not observed. Experiments with phytochrome mutants showed that far-red light was perceived exclusively by phyA, red light was perceived by both phyA and phyB, and phyC had little or no role in growth inhibition or coiling of the seminal roots. These results also suggest that other blue-light photoreceptors are involved in growth inhibition of the seminal roots. Fluence-response curve analyses showed that phyA and phyB control very low-fluence response and low-fluence response, respectively, in the seminal roots. This was essentially the same as the growth inhibition previously observed at the late stage of coleoptile development (80 h after germination). The photoperceptive site for the root growth inhibition appeared to be the roots themselves. All three phytochrome species of rice were detected immunochemically in roots.

Phytochromes are the sole photoreceptors for perceiving red/far-red light in rice.

Phytochromes are believed to be solely responsible for red and far-red light perception, but this has never been definitively tested. To directly address this hypothesis, a phytochrome triple mutant (phyAphyBphyC) was generated in rice (Oryza sativa L. cv. Nipponbare) and its responses to red and far-red light were monitored. Since rice only has three phytochrome genes (PHYA, PHYB and PHYC), this mutant is completely lacking any phytochrome. Rice seedlings grown in the dark develop long coleoptiles while undergoing regular circumnutation. The phytochrome triple mutants also show this characteristic skotomorphogenesis, even under continuous red or far-red light. The morphology of the triple mutant seedlings grown under red or far-red light appears completely the same as etiolated seedlings, and they show no expression of the light-induced genes. This is direct evidence demonstrating that phytochromes are the sole photoreceptors for perceiving red and far-red light, at least during rice seedling establishment. Furthermore, the shape of the triple mutant plants was dramatically altered. Most remarkably, triple mutants extend their internodes even during the vegetative growth stage, which is a time during which wild-type rice plants never elongate their internodes. The triple mutants also flowered very early under long day conditions and set very few seeds due to incomplete male sterility. These data indicate that phytochromes play an important role in maximizing photosynthetic abilities during the vegetative growth stage in rice.

Phytochrome-mediated inhibition of coleoptile growth in rice: age-dependency and action spectra.

Phytochrome has been shown to be the major photoreceptor involved in the photo-inhibition of coleoptile growth in Japonica-type rice (Oryza sativa L.). We have characterized this typical photomorphogenetic response of rice using mutants deficient in phytochrome A (phyA) and phytochrome B (phyB) and with respect to age-dependency and action spectra. Seedlings were irradiated with a pulse of light 40 h or 80 h after germination (i.e. at an early or late developmental stage) and the final coleoptile length of these seedlings was determined. A saturating pulse of red light (R) had a stronger effect when it was given in the late stage than in the early stage. It was found that the photoinhibition is mediated by both the phyA and the phyB in the late stage but predominantly by phyB in the early stage. Consistent with many other reported responses, the photo-inhibition in the phyA mutant, which was observed in the early and late developmental stages and is thought to be mediated mainly by phyB, occurred in the low-fluence range (10(1)-10(3) micromol m(-2)) of R and was far-red-light (FR)-reversible; the photo-inhibition in the phyB mutant, which was observed in the late developmental stage and is thought to be mediated mainly by phyA, occurred in the very-low-fluence range (10(-2)-10(0) micromol m(-2)) and was FR-irreversible. The action spectra (350-800 nm at 50 nm intervals) obtained at the two developmental stages using phyA and phyB mutants indicated that both the phyB-mediated low-fluence response and the phyA-mediated very-low-fluence response have a major peak at 650 nm and a minor peak at 400 nm.

Two native pools of phytochrome A in monocots: Evidence from fluorescence investigations of phytochrome mutants of rice.

Fluorescence investigations of phytochrome (phy) in rice (Oryza sativa L. cv. Nipponbare) mutants deficient in phyA, phyB and phyA plus phyB were performed. Total content of the pigment (P(tot)) and its spectroscopic and photochemical characteristics were determined in different parts of the dark-grown and far-red light (FR)-grown coleoptiles. Spectroscopically, phyA in the phyB mutant was identical to phyA in the wild-type (WT) and the extent of the conversion from Pr to lumi-R at 85 K was the same for phyA in both lines and varied similarly, depending on the part of the coleoptile used. The latter finding proved that phyA in rice is heterogeneous and comprises two phyA populations, phyA' and phyA". Functional properties of phyA were also determined. In the dark the phyB mutant had a higher content of phyA, inactive protochlorophyllide (Pchlide633) and active protochlorophyllide (Pchlide655) than WT and its coleoptile was longer, indicating that phyB may affect the development of WT seedlings in the dark. Constant FR drastically reduced the content of phyA, Pchlide633 and Pchlide655 and brought about coleoptile shortening and appearance of the first leaf, whereas pulsed FR of equal fluence was less effective. This suggested that the reactions were primarily of the high irradiance responses type, which are likely to be mediated by phyA'. The effects on protochlorophyllide biosynthesis and growth responses type were more pronounced in the phyB mutant than in the WT seedlings, which can be connected with the higher phyA' content in the phyB mutant and/or phyB interference with its action in WT seedlings. In the phyA mutant induction of Pchlide633 and Pchlide655 biosynthesis was observed under constant FR, indicating that phyC may be responsible for this effect.

Distinct and cooperative functions of phytochromes A, B, and C in the control of deetiolation and flowering in rice.

We have isolated phytochrome B (phyB) and phyC mutants from rice (Oryza sativa) and have produced all combinations of double mutants. Seedlings of phyB and phyB phyC mutants exhibited a partial loss of sensitivity to continuous red light (Rc) but still showed significant deetiolation responses. The responses to Rc were completely canceled in phyA phyB double mutants. These results indicate that phyA and phyB act in a highly redundant manner to control deetiolation under Rc. Under continuous far-red light (FRc), phyA mutants showed partially impaired deetiolation, and phyA phyC double mutants showed no significant residual phytochrome responses, indicating that not only phyA but also phyC is involved in the photoperception of FRc in rice. Interestingly, the phyB phyC double mutant displayed clear R/FR reversibility in the pulse irradiation experiments, indicating that both phyA and phyB can mediate the low-fluence response for gene expression. Rice is a short-day plant, and we found that mutation in either phyB or phyC caused moderate early flowering under the long-day photoperiod, while monogenic phyA mutation had little effect on the flowering time. The phyA mutation, however, in combination with phyB or phyC mutation caused dramatic early flowering.

Suppression of the floral activator Hd3a is the principal cause of the night break effect in rice.

A short exposure to light in the middle of the night causes inhibition of flowering in short-day plants. This phenomenon is called night break (NB) and has been used extensively as a tool to study the photoperiodic control of flowering for many years. However, at the molecular level, very little is known about this phenomenon. In rice (Oryza sativa), 10 min of light exposure in the middle of a 14-h night caused a clear delay in flowering. A single NB strongly suppressed the mRNA of Hd3a, a homolog of Arabidopsis thaliana FLOWERING LOCUS T (FT), whereas the mRNAs of OsGI and Hd1 were not affected. The NB effect on Hd3a mRNA was maximal in the middle of the 14-h night. The phyB mutation abolished the NB effect on flowering and Hd3a mRNA, indicating that the NB effect was mediated by phytochrome B. Because expression of the other FT-like genes was very low and not appreciably affected by NB, our results strongly suggest that the suppression of Hd3a mRNA is the principal cause of the NB effect on flowering in rice.

Salt stress inhibits the repair of photodamaged photosystem II by suppressing the transcription and translation of psbA genes in synechocystis.

Light stress and salt stress are major environmental factors that limit the efficiency of photosynthesis. However, we have found that the effects of light and salt stress on photosystem II (PSII) in the cyanobacterium Synechocystis sp. PCC 6803 are completely different. Strong light induced photodamage to PSII, whereas salt stress inhibited the repair of the photodamaged PSII and did not accelerate damage to PSII directly. The combination of light and salt stress appeared to inactivate PSII very rapidly as a consequence of their synergistic effects. Radioactive labeling of cells revealed that salt stress inhibited the synthesis of proteins de novo and, in particular, the synthesis of the D1 protein. Northern- and western-blotting analyses demonstrated that salt stress inhibited the transcription and the translation of psbA genes, which encode D1 protein. DNA microarray analysis indicated that the light-induced expression of various genes was suppressed by salt stress. Thus, our results suggest that salt stress inhibits the repair of PSII via suppression of the activities of the transcriptional and translational machinery.