Barley RIC157, a potential RACB scaffold protein, is involved in susceptibility to powdery mildewEngelhardt, Stefan; Trutzenberg, Adriana; Kopischke, Michaela; Probst, Katja; McCollum, Christopher; Hofer, Johanna; Hückelhoven, Ralph
doi: 10.1007/s11103-022-01329-xpmid: 36562946
Key messageCRIB motif-containing barley RIC157 is a novel ROP scaffold protein that interacts directly with barley RACB, promotes susceptibility to fungal penetration, and colocalizes with RACB at the haustorial neck.AbstractSuccessful obligate pathogens benefit from host cellular processes. For the biotrophic ascomycete fungus Blumeria hordei (Bh) it has been shown that barley RACB, a small monomeric G-protein (ROP, Rho of plants), is required for full susceptibility to fungal penetration. The susceptibility function of RACB probably lies in its role in cell polarity, which may be co-opted by the pathogen for invasive ingrowth of its haustorium. However, how RACB supports fungal penetration success and which other host proteins coordinate this process is incompletely understood. RIC (ROP-Interactive and CRIB-(Cdc42/Rac Interactive Binding) motif-containing) proteins are considered scaffold proteins which can interact directly with ROPs via a conserved CRIB motif. Here we describe a previously uncharacterized barley RIC protein, RIC157, which can interact directly with RACB in planta. We show that, in the presence of constitutively activated RACB, RIC157 shows a localization at the cell periphery/plasma membrane, whereas it otherwise localizes to the cytoplasm. RIC157 appears to mutually stabilize the plasma membrane localization of the activated ROP. During fungal infection, RIC157 and RACB colocalize at the penetration site, particularly at the haustorial neck. Additionally, transiently overexpressed RIC157 renders barley epidermal cells more susceptible to fungal penetration. We discuss that RIC157 may promote fungal penetration into barley epidermal cells by operating probably downstream of activated RACB.
Specific alterations in riboproteomes composition of isonicotinic acid treated arabidopsis seedlingsFakih, Zainab; Plourde, Mélodie B.; Nkouankou, Charlène Eugénie Tomi; Fourcassié, Victor; Bourassa, Sylvie; Droit, Arnaud; Germain, Hugo
doi: 10.1007/s11103-022-01332-2pmid: 36790538
Plants have developed strategies to deal with the great variety of challenges they are exposed to. Among them, common targets are the regulation of transcription and translation to finely modulate protein levels during both biotic and abiotic stresses. Increasing evidence suggests that ribosomes are highly adaptable modular supramolecular structures which remodel to adapt to stresses. Each Arabidopsis thaliana ribosome consists of approximately 81 distinct ribosomal proteins (RPs), each of which is encoded by two to seven genes. To investigate the identity of ribosomal proteins of the small subunit (RPS) and of the large subunit (RPL) as well as ribosomes-associated proteins, we analysed by LC/MS/MS immunopurified ribosomes from A. thaliana leaves treated with isonicotinic acid (INA), an inducer of plant innate immunity. We quantified a total of 2084 proteins. 165 ribosome-associated proteins showed increased abundance while 52 were less abundant. Of the 52 identified RPS (from a possibility of 104 encoding genes), 15 were deregulated. Similarly, from the 148 possible RPL, 80 were detected and 9 were deregulated. Our results revealed potential candidates involved in innate immunity that could be interesting targets for functional genomic studies.
The lipoxygenase OsLOX10 affects seed longevity and resistance to saline-alkaline stress during rice seedlingsWang, Fuxiang; Xu, Huibin; Zhang, Ling; Shi, Yunrui; Song, Yu; Wang, Xinyue; Cai, Qiuhua; He, Wei; Xie, Huaan; Zhang, Jianfu
doi: 10.1007/s11103-023-01334-8pmid: 36867321
Prolonged storage of rice seeds can lead to a decrease in seed vigor and seedling quality. The Lipoxygenase (LOX) gene family is widely distributed in plants, and LOX activity is closely related to seed viability and stress tolerance. In this study, the lipoxygenase OsLOX10 gene from the 9-lipoxygenase metabolic pathway was cloned from rice, and its roles in determining seed longevity and tolerance to saline-alkaline stress caused by Na2CO3 in rice seedlings were mainly investigated. CRISPR/Cas9 knockout of OsLOX10 increased seed longevity compared with the wild-type and OsLOX10 overexpression lines in response to artificial aging. The expression levels of other 9-lipoxygenase metabolic pathway related genes, such as LOX1, LOX2 and LOX3, were increased in the LOX10 overexpression lines. Quantitative real-time PCR and histochemical staining analysis showed that the expression of LOX10 was highest in seed hulls, anthers and the early germinating seeds. KI-I2 staining of starch showed that LOX10 could catalyze the degradation of linoleic acid. Furthermore, we found that the transgenic lines overexpressing LOX10 showed better tolerance to saline-alkaline stress than the wild-type and knockout mutant lines. Overall, our study demonstrated that the knockout LOX10 mutant increased seed longevity, whereas overexpression of LOX10 enhanced tolerance to saline-alkaline stress in rice seedlings.
Citrate synthase from Cyanidioschyzon merolae exhibits high oxaloacetate and acetyl-CoA catalytic efficiencyNishii, Maki; Ito, Shoki; Osanai, Takashi
doi: 10.1007/s11103-023-01335-7pmid: 36884198
Citrate synthase (CS) catalyzes the reaction that produces citrate and CoA from oxaloacetate and acetyl-CoA in the tricarboxylic acid (TCA) cycle. All TCA cycle enzymes are localized to the mitochondria in the model organism, the red alga Cyanidioschyzon merolae. The biochemical properties of CS have been studied in some eukaryotes, but the biochemical properties of CS in algae, including C. merolae, have not been studied. We then performed the biochemical analysis of CS from C. merolae mitochondria (CmCS4). The results showed that the kcat/Km of CmCS4 for oxaloacetate and acetyl-CoA were higher than those of the cyanobacteria, such as Synechocystis sp. PCC 6803, Microcystis aeruginosa PCC 7806 and Anabaena sp. PCC 7120. Monovalent and divalent cations inhibited CmCS4, and in the presence of KCl, the Km of CmCS4 for oxaloacetate and acetyl-CoA was higher in the presence of MgCl2, the Km of CmCS4 for oxaloacetate and acetyl-CoA was higher and kcat lower. However, in the presence of KCl and MgCl2, the kcat/Km of CmCS4 was higher than those of the three cyanobacteria species. The high catalytic efficiency of CmCS4 for oxaloacetate and acetyl-CoA may be a factor in the increased carbon flow into the TCA cycle in C. merolae.
Transcriptomic-based analysis to identify candidate genes for blue color rose breedingJiang, Sheng-Hang; Wang, Huan-Huan; Zhang, Ren; Yang, Zhen-Yu; He, Guo-Ren; Ming, Feng
doi: 10.1007/s11103-023-01337-5pmid: 36913074
Key messageAnalysis of the flower color formation mechanism of ‘Rhapsody in Blue’ by BF and WF transcriptomes reveals that RhF3’H and RhGT74F2 play a key role in flower color formation.AbstractRosa hybrida has colorful flowers and a high ornamental value. Although rose flowers have a wide range of colors, no blue roses exist in nature, and the reason for this is unclear. In this study, the blue-purple petals (BF) of the rose variety ‘Rhapsody in Blue’ and the white petals (WF) of its natural mutant were subjected to transcriptome analysis to find genes related to the formation of the blue-purple color. The results showed that the anthocyanin content was significantly higher in BF than in WF. A total of 1077 differentially expressed genes (DEGs) were detected by RNA-Seq analysis, of which 555 were up-regulated and 522 were down-regulated in the WF vs. BF petals. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses of the DEGs revealed that a single gene up-regulated in BF was related to multiple metabolic pathways including metabolic process, cellular process, protein-containing complex, etc. Additionally, the transcript levels of most of the structural genes related to anthocyanin synthesis were significantly higher in BF than in WF. Selected genes were analyzed by qRT-PCR and the results were highly consistent with the RNA-Seq results. The functions of RhF3'H and RhGT74F2 were verified by transient overexpression analyses, and the results confirmed that both affect the accumulation of anthocyanins in ‘Rhapsody in Blue’. We have obtained comprehensive transcriptome data for the rose variety ‘Rhapsody in Blue’. Our results provide new insights into the mechanisms underlying rose color formation and even blue rose formation.