We present a simple, rapid and low‐cost method for isolating high yield of Arabidopsis chloroplasts that can be used to study chloroplast protein import. Efficiency isolation was dependent upon the ratio between amount plant tissue buffer volume, size speed homogenisation equipment, beaker. The import proved useful when characterising different precursor proteins, developmental stages import‐defective mutants. Time‐course experiments enabled measurement rates in linear range. Compared...

Abstract Monogalactosyldiacylglycerol (MGDG) is the major lipid constituent of chloroplast membranes and has been proposed to act directly in several important plastidic processes, particularly during photosynthesis. In this study, effect MGDG deficiency, as observed monogalactosyldiacylglycerol synthase1-1 (mgd1-1) mutant, on protein targeting, phototransformation pigments, photosynthetic light reactions was analyzed. The targeting plastid proteins into or across envelope, thylakoid...

Summary The Arabidopsis phosphate transporter PHT 4;1 was previously localized to the chloroplast thylakoid membrane. Here we investigated physiological consequences of absence for photosynthesis and plant growth. In standard growth conditions, two independent knockout mutant lines displayed significantly reduced leaf size biomass but normal phosphorus content. When mutants were grown in high‐phosphate levels increased phenotype suppressed. Photosynthetic measurements indicated that stromal...

Large and rapidly increasing areas of salt-affected soils are posing major challenges for the agricultural sector. Most fields used important food crop Triticum aestivum (wheat) expected to be within 50 years. To counter associated problems, it is essential understand molecular mechanisms involved in salt stress responses tolerance, thereby enabling their exploitation development salt-tolerant varieties. The myeloblastosis (MYB) family transcription factors key regulators both biotic abiotic...

Toc64/OEP64 was identified biochemically in pea as a putative component of the chloroplast protein import apparatus. In Arabidopsis, three paralogous genes (atTOC64-III, atTOC64-V and atTOC64-I) encode Toc64-related proteins, these have been reported to localize chloroplasts, mitochondria cytosol, respectively. To assess role atToc64-III an vivo context, we characterized Arabidopsis knockout mutants. The absence detectable defects toc64-III single mutants raised possibility redundancy,...

The molecular chaperone ClpC/Hsp93 is essential for chloroplast function in vascular plants. ClpC has long been held to act both independently and as the regulatory partner ATP-dependent Clp protease, yet this many other important characteristics remain unclear. In study, we reveal that of two near-identical paralogs (ClpC1 ClpC2) Arabidopsis chloroplasts, along with closely related ClpD, it ClpC1 most abundant throughout leaf maturation. An unexpectedly large proportion proteins (30% total...

Abstract Plants defend themselves against microbial pathogens through a range of highly sophisticated and integrated molecular systems. Recognition pathogen-secreted effector proteins often triggers the hypersensitive response (HR), complex multicellular defense reaction where programmed cell death cells surrounding primary site infection is prominent feature. Even though HR was described almost century ago, cell-to-cell factors acting at local level generating full have remained obscure. In...

Abstract Background Triticum aestivum (wheat) is one of the world’s oldest crops and has been used for >8000 years as a food crop in North Africa, West Asia Europe. Today, wheat most important sources grain humans, cultivated on greater areas land than any other crop. As human population increases soil salinity becomes more prevalent, there increased pressure breeders to develop salt-tolerant varieties order meet growing demands yield quality. Here we developed mutant using moderately...

Abstract The evolutionary success of plants relies to a large extent on their extraordinary ability adapt changes in environment. These adaptations require that balance growth with stress responses. Plant hormones are crucial mediators orchestrating the underlying adaptive processes. However, whether and how growth-related hormone auxin stress-related jasmonic acid, salicylic abscisic acid (ABA) coordinated remains largely elusive. Here, we analyse physiological role AMIDASE 1 (AMI1)...

Abstract Background Rice growth is frequently affected by salinity. When exposed to high salinity, rice seed germination and seedling establishment are significantly inhibited. With the promotion of direct-seeding in Asia, improving under salt stress crucial for breeding. Results In this study, an indica landrace Wujiaozhan (WJZ) was identified with germinability stress. A BC 1 F 2 population derived from crossing WJZ/Nip ( japonica , Nipponbare)//Nip, used quantitative trait loci (QTL)...

Thylakoid biogenesis is a crucial step for plant development involving the combined action of many cellular actors. CPSAR1 shown here to be required normal organization mature thylakoid stacks, and ultimately embryo development. chloroplast protein that has dual localization in stroma inner envelope membrane, according microscopy studies subfractionation analysis. close Obg nucleotide binding subfamily displays GTPase activity, as demonstrated by vitro assays. Disruption gene via T-DNA...

Proteins and lipids are known to be transported targeted cytosolic compartments in vesicles. A similar system chloroplasts is suggested transfer from the inner envelope thylakoids. However, little about both possible cargo proteins required build a functional vesicle transport chloroplasts. few components have been suggested, but only one (CPSAR1) has verified location chloroplast This protein localized donor membrane (envelope) vesicles, not target (thylakoids) suggesting it plays role...

Abstract The protein targeting signal recognition particle (SRP) pathway in chloroplasts of higher plants has undergone dramatic evolutionary changes. It disposed its RNA, which is an essential SRP component bacteria, and uses a unique chloroplast-specific cpSRP43. Nevertheless, homologs the conserved SRP54 receptor, FtsY, are present plant chloroplasts. In this study, we analyzed phylogenetic distribution components photosynthetic organisms to elucidate evolution system. We identified...

When exposed to salt stress, leaves from dark‐grown wheat seedlings ( Triticum aestivum , cv. Giza 168) showed reduced accumulation of chlorophyll during irradiation. To elucidate the mechanism behind salt‐influenced reduction biosynthesis, we have investigated effect stress on spectral forms Pchlide, phototransformation Pchlide Chlide, Shibata shift, regeneration and 5‐aminolevulinic acid (ALA). We found that Chlide was not affected by stress. The blue shift (Shibata shift) newly formed...

High salinity causes ion imbalance and osmotic stress in plants. Leaf sections from 8-d-old dark-grown wheat (Triticum aestivum cv. Giza 168) were exposed to high salt (600 mM) the native arrangements of plastid pigments together with ultrastructure plastids studied using low-temperature fluorescence spectroscopy transmission electron microscopy. Although salt-treated leaves had highly swollen prothylakoids (PTs) prolamellar bodies (PLBs) regular. Accordingly, a slight intensity decrease...

Summary The atToc33 protein is one of several pre‐protein import receptors in the outer envelope Arabidopsis chloroplasts. It a GTPase with motifs characteristic such proteins, and its loss plastid 1 ( ppi1 ) mutant interferes photosynthesis‐related pre‐proteins, causing chlorotic phenotype plants. To assess significance cycling by atToc33, we generated point mutants predicted effects on GTP binding (K49R, S50N S50N/S51N), hydrolysis (G45R, G45V, Q68A N101A), both (G45R/K49N/S50R),...

Peripheral vesicles in plastids have been observed repeatedly, primarily proplastids and developing chloroplasts, which they are suggested to function thylakoid biogenesis. Previous observations of mature chloroplasts mainly concerned low temperature pretreated plants occasionally treated with inhibitors blocking vesicle fusion. Here, we show that such vesicle‐like structures occur not only proplastids, but also etioplasts, etio‐chloroplasts, leucoplasts, chromoplasts even transforming...

Chloroplast differentiation in angiosperm plants depends on the light-dependent conversion of protochlorophyllide to chlorophyllide by NADPH:protochlorophyllide oxidoreductase (PORA; EC 1.6.99.1), a nuclearly encoded protein. The protein import precursor form PORA into plastids was shown previously strictly depend presence its substrate protochlorophyllide. seemed follow novel, posttranslationally regulated route. Here we demonstrate that from barley is imported isolated independently as...