Effects of Cadmium Stress on Tartary Buckwheat Seedlings.

Cadmium (Cd) is a naturally occurring toxic heavy metal that adversely affects plant germination, growth, and development. While the effects of Cd have been described on many crop species including rice, maize, wheat and barley, few studies are available on cadmium's effect on Tartary buckwheat which is a traditional grain in China. We examined nine genotypes and found that 30 µM of Cd reduced the root length in seedlings by between 4 and 44% and decreased the total biomass by 7 to 31%, compared with Cd-free controls.

Reduced tillering and dwarfing genes alter root traits and rhizo-economics in wheat.

The tiller inhibition (tin) and Reduced height (Rht) genes strongly influence the carbon partitioning and architecture of wheat shoots, but their effects on the energy economy of roots have not been examined in detail. We examined multiple root traits in three sets of near-isogenic wheat lines (NILs) that differ in the tin gene or various dwarfing gene alleles (Rht-B1b, Rht-D1b, Rht-B1c and Rht-B1b + Rht-D1b) to determine their effects on root structure, anatomy and carbon allocation. The tin gene resulted in fewer tillers but more costly roots in an extreme tin phenotype with a Banks genetic background due to increases in root-to-shoot ratio, total root length, and whole root respiration.

A conditional mutation in a wheat (Triticum aestivum L.) gene regulating root morphology.

Characterisation and genetic mapping of a key gene defining root morphology in bread wheat. Root morphology is central to plants for the efficient uptake up of soil water and mineral nutrients. Here we describe a conditional mutant of hexaploid wheat (Triticum aestivum L.

Physical Mapping of QTLs for Root Traits in a Population of Recombinant Inbred Lines of Hexaploid Wheat.

Root architecture is key in determining how effective plants are at intercepting and absorbing nutrients and water. Previously, the wheat () cultivars Spica and Maringa were shown to have contrasting root morphologies. These cultivars were crossed to generate an F population of recombinant inbred lines (RILs) which was genotyped using a 90 K single nucleotide polymorphisms (SNP) chip.

Expression of the wheat multipathogen resistance hexose transporter Lr67res is associated with anion fluxes.

Many disease resistance genes in wheat (Triticum aestivum L.) confer strong resistance to specific pathogen races or strains, and only a small number of genes confer multipathogen resistance. The Leaf rust resistance 67 (Lr67) gene fits into the latter category as it confers partial resistance to multiple biotrophic fungal pathogens in wheat and encodes a Sugar Transport Protein 13 (STP13) family hexose-proton symporter variant.

A genome-wide association study (GWAS) identifies multiple loci linked with the natural variation for Al resistance in .

Acid soils limit yields of many important crops including canola (Brassica napus ), Australia's third largest crop. Aluminium (Al3+ ) stress is the main cause of this limitation primarily because the toxic Al3+ present inhibits root growth. Breeding programmes do not target acid-soil tolerance in B.

Selection for early shoot vigour in wheat increases root hair length but reduces epidermal cell size of roots and leaves.

Six cycles of recurrent selection for early shoot vigour in wheat resulted in significant increases in leaf width and shoot biomass. Here, in replicated controlled-environment studies, the effect of early shoot vigour on root biomass, rhizosheath size, root hair length, and cell size in the roots and leaves was examined across different cycles of selection. Increased shoot vigour was associated with greater root biomass, larger rhizosheath size, and longer root hairs.

Manipulating exudate composition from root apices shapes the microbiome throughout the root system.

Certain soil microorganisms can improve plant growth, and practices that encourage their proliferation around the roots can boost production and reduce reliance on agrochemicals. The beneficial effects of the microbial inoculants currently used in agriculture are inconsistent or short-lived because their persistence in soil and on roots is often poor. A complementary approach could use root exudates to recruit beneficial microbes directly from the soil and encourage inoculant proliferation.

ZmMATE6 from maize encodes a citrate transporter that enhances aluminum tolerance in transgenic Arabidopsis thaliana.

The yields of cereal crops grown on acidic soils are often reduced by aluminum (Al) toxicity because the prevalence of toxic Al cations increases as pH falls below 5.0. The Al-dependent release of citrate from resistant lines of maize is controlled by ZmMATE1 which encodes a multidrug and toxic compound extrusion (MATE) transporter protein.

The microbiomes on the roots of wheat (Triticum aestivum L.) and rice (Oryza sativa L.) exhibit significant differences in structure between root types and along root axes.

There is increasing interest in understanding how the microbial communities on roots can be manipulated to improve plant productivity. Root systems are not homogeneous organs but are comprised of different root types of various ages and anatomies that perform different functions. Relatively little is known about how this variation influences the distribution and abundance of microorganisms on roots and in the rhizosphere.

Peptide Nucleic Acid (PNA) Clamps to Reduce Co-amplification of Plant DNA During PCR Amplification of 16S rRNA Genes from Endophytic Bacteria.

High-throughput sequencing of universal bacterial 16S rRNA gene (16S rDNA) amplicons is a routine method for characterizing bacterial diversity in a range of environments. For eukaryotic host-associated communities, however, plastid and mitochondrial genes are often co-amplified with, and greatly outnumber, bacterial 16S rDNA. This makes it difficult to obtain sufficient numbers of target 16S rDNA sequences to characterize the diversity of endophytic bacterial communities.

A sterile hydroponic system for characterising root exudates from specific root types and whole-root systems of large crop plants.

Background: Plant roots release a variety of organic compounds into the soil which alter the physical, chemical and biological properties of the rhizosphere. Root exudates are technically challenging to measure in soil because roots are difficult to access and exudates can be bound by minerals or consumed by microorganisms. Exudates are easier to measure with hydroponically-grown plants but, even here, simple compounds such as sugars and organic acids can be rapidly assimilated by microorganisms.

Assessing How the Aluminum-Resistance Traits in Wheat and Rye Transfer to Hexaploid and Octoploid Triticale.

The mechanisms of aluminum (Al) resistance in wheat and rye involve the release of citrate and malate anions from the root apices. Many of the genes controlling these processes have been identified and their responses to Al treatment described in detail. This study investigated how the major Al resistance traits of wheat and rye are transferred to triticale (x Wittmack) which is a hybrid between wheat and rye.

The role of transposable elements in the evolution of aluminium resistance in plants.

Aluminium (Al) toxicity can severely reduce root growth and consequently affect plant development and yield. A mechanism by which many species resist the toxic effects of Al relies on the efflux of organic anions (OAs) from the root apices via OA transporters. Several of the genes encoding these OA transporters contain transposable elements (TEs) in the coding sequences or in flanking regions.

The Wheat Gene from the Sugar Transport Protein 13 Family Confers Multipathogen Resistance in Barley.

Fungal pathogens are a major constraint to global crop production; hence, plant genes encoding pathogen resistance are important tools for combating disease. A few resistance genes identified to date provide partial, durable resistance to multiple pathogens and the wheat () Lr67 hexose transporter variant (Lr67res) fits into this category. Two amino acids differ between the wild-type and resistant alleles - G144R and V387L.

Altered Expression of the Malate-Permeable Anion Channel OsALMT4 Reduces the Growth of Rice Under Low Radiance.

We examined the function of in rice ( L.) which is a member of the aluminum-activated malate transporter family. Previous studies showed that OsALMT4 localizes to the plasma membrane and that expression in transgenic rice lines results in a constitutive release of malate from the roots.

Do longer root hairs improve phosphorus uptake? Testing the hypothesis with transgenic Brachypodium distachyon lines overexpressing endogenous RSL genes.

Mutants without root hairs show reduced inorganic orthophosphate (Pi) uptake and compromised growth on soils when Pi availability is restricted. What is less clear is whether root hairs that are longer than wild-type provide an additional benefit to phosphorus (P) nutrition. This was tested using transgenic Brachypodium lines with longer root hairs.

Altered Expression of a Malate-Permeable Anion Channel, OsALMT4, Disrupts Mineral Nutrition.

Aluminum-activated malate transporters (ALMTs) form a family of anion channels in plants, but little is known about most of its members. This study examined the function of from rice (). We show that is expressed in roots and shoots and that the OsALMT4 protein localizes to the plasma membrane.

Aluminum Complexation with Malate within the Root Apoplast Differs between Aluminum Resistant and Sensitive Wheat Lines.

In wheat (), it is commonly assumed that Al is detoxified by the release of organic anions into the rhizosphere, but it is also possible that detoxification occurs within the apoplast and symplast of the root itself. Using Al-resistant (ET8) and Al-sensitive (ES8) near-isogenic lines of wheat, we utilized traditional and synchrotron-based approaches to provide analyses of the distribution and speciation of Al within root tissues. Some Al appeared to be complexed external to the root, in agreement with the common assumption.

Root hairs enable high transpiration rates in drying soils.

Do root hairs help roots take up water from the soil? Despite the well-documented role of root hairs in phosphate uptake, their role in water extraction is controversial. We grew barley (Hordeum vulgare cv Pallas) and its root-hairless mutant brb in a root pressure chamber, whereby the transpiration rate could be varied whilst monitoring the suction in the xylem. The method provides accurate measurements of the dynamic relationship between the transpiration rate and xylem suction.

Microbiome and Exudates of the Root and Rhizosphere of Brachypodium distachyon, a Model for Wheat.

The rhizosphere microbiome is regulated by plant genotype, root exudates and environment. There is substantial interest in breeding and managing crops that host root microbial communities that increase productivity. The eudicot model species Arabidopsis has been used to investigate these processes, however a model for monocotyledons is also required.

A chimeric protein of aluminum-activated malate transporter generated from wheat and Arabidopsis shows enhanced response to trivalent cations.

TaALMT1 from wheat (Triticum aestivum) and AtALMT1 from Arabidopsis thaliana encode aluminum (Al)-activated malate transporters, which confer acid-soil tolerance by releasing malate from roots. Chimeric proteins from TaALMT1 and AtALMT1 (Ta::At, At::Ta) were previously analyzed in Xenopus laevis oocytes. Those studies showed that Al could activate malate efflux from the Ta::At chimera but not from At::Ta.