Phosphate-deprivation and damage signalling by extracellular ATP.

Phosphate deprivation compromises plant productivity and modulates immunity. DAMP signalling by extracellular ATP (eATP) could be compromised under phosphate deprivation by the lowered production of cytosolic ATP and the need to salvage eATP as a nutritional phosphate source. Phosphate-starved roots of can still sense eATP, indicating robustness in receptor function.

Arabidopsis thaliana CYCLIC NUCLEOTIDE-GATED CHANNEL2 mediates extracellular ATP signal transduction in root epidermis.

Damage can be signalled by extracellular ATP (eATP) using plasma membrane (PM) receptors to effect cytosolic free calcium ion ([Ca ] ) increase as a second messenger. The downstream PM Ca channels remain enigmatic. Here, the Arabidopsis thaliana Ca channel subunit CYCLIC NUCLEOTIDE-GATED CHANNEL2 (CNGC2) was identified as a critical component linking eATP receptors to downstream [Ca ] signalling in roots.

Annexin 1 Is a Component of eATP-Induced Cytosolic Calcium Elevation in Roots.

Extracellular ATP (eATP) has long been established in animals as an important signalling molecule but this is less understood in plants. The identification of DORN1 (Does Not Respond to Nucleotides) as the first plant eATP receptor has shown that it is fundamental to the elevation of cytosolic free Ca ([Ca]) as a possible second messenger. eATP causes other downstream responses such as increase in reactive oxygen species (ROS) and nitric oxide, plus changes in gene expression.

Phosphate Deprivation Can Impair Mechano-Stimulated Cytosolic Free Calcium Elevation in Roots.

The root tip responds to mechanical stimulation with a transient increase in cytosolic free calcium as a possible second messenger. Although the root tip will grow through a heterogeneous soil nutrient supply, little is known of the consequence of nutrient deprivation for such signalling. Here, the effect of inorganic phosphate deprivation on the root's mechano-stimulated cytosolic free calcium increase is investigated.

DORN1/P2K1 and purino-calcium signalling in plants: making waves with extracellular ATP.

Background And Aims: Extracellular ATP governs a range of plant functions, including cell viability, adaptation and cross-kingdom interactions. Key functions of extracellular ATP in leaves and roots may involve an increase in cytosolic free calcium as a second messenger ('calcium signature'). The main aim here was to determine to what extent leaf and root calcium responses require the DORN1/P2K1 extracellular ATP receptor in Arabidopsis thaliana.

Iron availability modulates the root calcium signature evoked by exogenous ATP.

Plants use changes in cytosolic free Ca ("signatures") to encode information from the specific signals generated in development, immunity and stress perception. Phosphate availability has a significant impact on the root calcium signatures generated in response to abiotic stress stimuli and exogenous purine nucleotides. In the case of the response to exogenous ATP, the effect of low phosphate availability is linked to abnormal iron and reactive oxygen species accumulation with iron deprivation's restoring normal signature dynamics.

Phosphate Starvation Alters Abiotic-Stress-Induced Cytosolic Free Calcium Increases in Roots.

Phosphate (Pi) deficiency strongly limits plant growth, and plant roots foraging the soil for nutrients need to adapt to optimize Pi uptake. Ca is known to signal in root development and adaptation but has to be tightly controlled, as it is highly toxic to Pi metabolism. Under Pi starvation and the resulting decreased cellular Pi pool, the use of cytosolic free Ca ([Ca]) as a signal transducer may therefore have to be altered.

Impairment in karrikin but not strigolactone sensing enhances root skewing in Arabidopsis thaliana.

Roots form highly complex systems varying in growth direction and branching pattern to forage for nutrients efficiently. Here mutations in the KAI2 (KARRIKIN INSENSITIVE) α/β-fold hydrolase and the MAX2 (MORE AXILLARY GROWTH 2) F-box leucine-rich protein, which together perceive karrikins (smoke-derived butenolides), caused alteration in root skewing in Arabidopsis thaliana. This phenotype was independent of endogenous strigolactones perception by the D14 α/β-fold hydrolase and MAX2.

Responses of contrasting rice genotypes to excess manganese and their implications for lignin synthesis.

Manganese (Mn) toxicity is frequently encountered in crops grown on soils with low pH or low redox potential, and harmful to plant development and growth. This study aimed at exploring adaptive mechanisms to Mn toxicity in rice, and investigated the effects of Mn toxicity on shoot lignification. Sixteen rice genotypes were grown in hydroponic solutions and exposed to normal (0.

Calcium-Mediated Abiotic Stress Signaling in Roots.

Roots are subjected to a range of abiotic stresses as they forage for water and nutrients. Cytosolic free calcium is a common second messenger in the signaling of abiotic stress. In addition, roots take up calcium both as a nutrient and to stimulate exocytosis in growth.

Loci, genes, and mechanisms associated with tolerance to ferrous iron toxicity in rice (Oryza sativa L.).

A genome-wide association study in rice yielded loci and candidate genes associated with tolerance to iron toxicity, and revealed biochemical mechanisms associated with tolerance in contrasting haplotypes. Iron toxicity is a major nutrient disorder affecting rice. Therefore, understanding the genetic and physiological mechanisms associated with iron toxicity tolerance is crucial in adaptive breeding and biofortification.

Genetic dissection of ozone tolerance in rice (Oryza sativa L.) by a genome-wide association study.

Tropospheric ozone causes various negative effects on plants and affects the yield and quality of agricultural crops. Here, we report a genome-wide association study (GWAS) in rice (Oryza sativa L.) to determine candidate loci associated with ozone tolerance.

Genetic and physiological analysis of tolerance to acute iron toxicity in rice.

Background: Fe toxicity occurs in lowland rice production due to excess ferrous iron (Fe(2+)) formation in reduced soils. To contribute to the breeding for tolerance to Fe toxicity in rice, we determined quantitative trait loci (QTL) by screening two different bi-parental mapping populations under iron pulse stresses (1,000 mg L(-1) = 17.9 mM Fe(2+) for 5 days) in hydroponic solution, followed by experiments with selected lines to determine whether QTLs were associated with iron exclusion (i.