Identification of molecular integrators shows that nitrogen activelycontrolsthephosphatestarvationresponseinplants

Nitrogen (N) and phosphorus (P) are key macronutrients sustaining plant growth and crop yield and ensuring food security worldwide. Understanding how plants perceive and interpret the combinatorial nature of these signals thus has important agricultural implications within the context of (1) increased food demand, (2) limited P supply, and (3) environmental pollution due to N fertilizer usage. Here, we report the discovery of an active control of P starvation response (PSR) by a combination of local and long-distance N signaling pathways in plants. We show that, in Arabidopsis (Arabidopsis thaliana), the nitrate transceptor CHLORINA1/NITRATE TRANSPORTER1.1 (CHL1/NRT1.1) is a component of this signaling crosstalk. We also demonstrate that this crosstalk is dependent on the control of the accumulation and turnover by N of the transcription factor PHOSPHATE STARVATION RESPONSE1 (PHR1), a master regulator of P sensing and signaling. We further show an important role of PHOSPHATE2 (PHO2) as an integrator of the N availability into the PSR since the effect of N on PSR is strongly affected in pho2 mutants. We finally show that PHO2 and NRT1.1 influence each other’s transcript levels. These observations are summarized in a model representing a framework with several entry points where N signal influence PSR. Finally, we demonstrate that this phenomenon is conserved in rice (Oryza sativa) and wheat (Triticum aestivum), opening biotechnological perspectives in crop plants.This work was supported in the Honude group (Biochemistry & Plant Molecular Physiology) by Agence Nationale de la Recherche (IMANA ANR-14-CE19-0008 with a doctoral fellowship to A.S.), by the Centre National de la Recherche Scientifique (CNRS LIA-CoopNet to G.K.), and by the National Science Foundation (NSF IOS 1339362-NutriNet). Research in V.R.’s laboratory was funded by the Ministry of Economy and Competitiveness and AEI/FEDER/European (grants BIO2013-46539-R and BIO2016-80551-R)

Worldwide genetic diversity for mineral element concentrations in rice grain

With the aim of identifying rice (Oryza spp.) germplasm having enhanced grain nutritional value, the mineral nutrient and trace element concentrations (or ionome) of whole (unmilled) grains from a set of 1763 rice accessions of diverse geographic and genetic origin were evaluated. Seed for analysis of P, Mg, K, S, Ca, As, Cd, Co, Cu, Fe, Mn, Mo, Ni, Rb, Sr, and Zn concentrations by inductively coupled plasma mass spectrometry was produced over 2 yr in Beaumont, TX, under both flooded and unflooded watering regimes. The distributions of all element concentrations analyzed were skewed toward higher concentration. A significant portion of this ionomic variation has a genetic basis (broad sense heritabilities 0.14–0.75), indicating an ability to breed for improved grain concentration of all elements except possibly Ni. Variation in grain elemental concentrations was not strongly associated with plant height, heading time, or grain shape, suggesting these physiological factors are not of primary importance in controlling ionomic variation in rice grain. Accessions high in specific elements were sometimes found to have similar genetic or geographic origins, suggesting they share a heritable mechanism underlying their enhanced ionomes. For example, accessions with high Ca, Mg, or K were more common in the indica than in the japonica subgroup; low As was most common among temperate japonica accessions; and several lines high in Mo originated in Malaysia or adjacent Brunei

Zinc availability modulates plant growth and 1 immune responses via AZI1

Zinc is an essential micronutrient for all living organisms and is involved in a plethora of processes including growth and development, and immunity. However, it is unknown if there is a common genetic and molecular basis underlying multiple facets of zinc function. Here we used natural variation in Arabidopsis thaliana to study the role of zinc in regulating growth. We identify allelic variation of the systemic immunity gene AZI1 as a key for determining root growth responses to low zinc conditions. We further demonstrate that this gene is important for modulating root growth depending on the zinc and defence status. Finally, we show that the interaction of the immunity signal azelaic acid and zinc level to regulate root growth is conserved in rice. This work demonstrates that there is a common genetic and molecular basis for multiple zinc dependent processes and that nutrient cues can determine the balance of plant growth and immune responses in plants

Boron requirement for vegetative growth of Sacha inchi (Plukentia volubilis L.)

Sachi inchi is a useful traditional plant in South America that has recently gained notoriety as a nutritional food crop and hence is being cultivated outside its native range. In Thailand, the crop is being grown on soils where boron (B) may be limiting to growth. To determine the response of early vegetative growth of sacha inchi to B supply, to identify B deficiency symptoms, and to define leaf B concentrations for optimum growth. The two experiments were conducted in sand-culture pot arranged in a randomized complete block design with three independent replications. Plants were grown in the preliminary experiment consisted of complete nutrient solution and complete nutrient solution without B. The main experiment was continued by growing plants in the five series of B rate (0, 2.5, 5.0, 7.5 and 10.0 µM B). Plant growth parameters were recorded and B concentration in different plant parts were analyzed. B deficiency strongly inhibited root and shoot development causing stunting and organ malformation. In a sand-culture experiment, maximum growth was obtained with 7.5 µM B and 10 µM B reduced growth. Leaf B concentration of 27–29 mg kg−1 was associated with 90% of maximum vegetative yield. Symptoms of B deficiency and the foliar B concentrations are useful for extension workers and producers looking to improve the productivity of sacha inchi on nutrient poor soils

Genotypic variation in milling depression of iron and zinc concentration in rice grain

Background and aims: The loss of iron and zinc during milling to produce white rice can have serious consequences for human health. Therefore, the objective was to evaluate Fe and Zn partitioning between the endosperm, bran and embryo, and the milling loss of these nutrients among Thai rice genotypes. Methods: Concentrations of iron and zinc and their partitioning to different parts of the grain were examined in 15 genotypes of Thai rice (10 belonging to the long-slender grain type) grown together under wetland condition. Results: The depression in grain Fe and Zn concentrations (24-60 and 10-58 %, respectively) on milling differed among rice genotypes and were affected by the extent of differential partitioning of Fe and Zn into different parts of the grain. For example, nearly 70 % of white rice Zn was allocated to the endosperm in contrast to only 43 % for Fe. Conclusions: Because of variation in milling loss of Fe and Zn, that can result from genotypic variation in the degree of milling and partitioning of Fe and Zn into different parts of the grain, we conclude that white rice Fe and Zn concentrations should not be inferred solely from brown rice concentrations of these nutrients

Distribution of iron and zinc in plant and grain of different rice genotypes grown under aerobic and wetland conditions

This paper examined the distribution of Fe and Zn in the plant and seed of different rice genotypes in different growing conditions. The Fe and Zn concentrations were determined in different plant tissues during the growth stages of 3 genotypes with high Fe and Zn check genotypes, and in different grain tissues of 15 genotypes grown in aerobic and wetland conditions. Iron and Zn were distributed differently in tissues of the rice plant, with the harvest index (panicle nutrient content as the % of the total above ground nutrients) at 3e4% for Fe and 54e74% for Zn. The concentrations of both Fe and Zn of the endosperm increased with the increasing proportion of the grain nutrient content allocated to the endosperm, but declined when the allocation to the bran fraction increased. The Fe concentrations of the de-husked caryopsis of rice grown in the aerobic soil and the Fe concentration of the de-husked caryopsis of rice grown in the wetland soil were closely related, but not in the endosperm Fe, while the grain Zn concentrations in the aerobic soil were found to correlate with the Zn concentrations in the wetland soil for both the de-husked caryopsis and the endosper

Zinc availability modulates plant growth and 1 immune responses via AZI1

preprint déposé dans bioRxivZinc is an essential micronutrient for all living organisms and is involved in a plethora of processes including growth and development, and immunity. However, it is unknown if there is a common genetic and molecular basis underlying multiple facets of zinc function. Here we used natural variation in Arabidopsis thaliana to study the role of zinc in regulating growth. We identify allelic variation of the systemic immunity gene AZI1 as a key for determining root growth responses to low zinc conditions. We further demonstrate that this gene is important for modulating root growth depending on the zinc and defence status. Finally, we show that the interaction of the immunity signal azelaic acid and zinc level to regulate root growth is conserved in rice. This work demonstrates that there is a common genetic and molecular basis for multiple zinc dependent processes and that nutrient cues can determine the balance of plant growth and immune responses in plants

Natural allelic variation of the AZI1 gene controls root growth under zinc-limiting condition.

Zinc is an essential micronutrient for all living organisms and is involved in a plethora of processes including growth and development, and immunity. However, it is unknown if there is a common genetic and molecular basis underlying multiple facets of zinc function. Here we used natural variation in Arabidopsis thaliana to study the role of zinc in regulating growth. We identify allelic variation of the systemic immunity gene AZI1 as a key for determining root growth responses to low zinc conditions. We further demonstrate that this gene is important for modulating primary root length depending on the zinc and defence status. Finally, we show that the interaction of the immunity signal azelaic acid and zinc level to regulate root growth is conserved in rice. This work demonstrates that there is a common genetic and molecular basis for multiple zinc dependent processes and that nutrient cues can determine the balance of plant growth and immune responses in plants

Variation in Grain Quality of Upland Rice from Luang Prabang Province, Lao PDR

Luang Prabang Province is located within the area recognized as the center of rice (Oryza sativa L.) diversity in Lao PDR. This study reported on grain quality characteristics of 60 upland rice seed samples sharing 49 variety names collected from 6 villages in Luang Prabang in 2015. Most of the samples has non-pigmented pericarp, while red pericarp was found in four samples and purple in five samples. Almost all of the samples were of large grain type, with glutinous endosperm in 70% and non-glutinous endosperm in 30%. The brown (unpolished) rice was found with a wide range of grain nutritional quality, including protein (9.2% ± 0.9%), Fe (15.9 ± 6.9 mg/kg), Zn (19.6 ± 2.1 mg/kg), anthocyanin (0.774 ± 0.880 mg/g), and anti-oxidative capacity (2.071 ± 1.373 mg/g). The varieties sharing similar names had similar morphological characteristics but varied in nutritional concentration, with required confirmation in genetic variation analysis. This study found that some rice varieties with high grain quality may benefit the farmers directly or could be used in varietal improvement programs

Antibiotic use in mandarin production (Citrus reticulata Blanco) in major mandarin-producing areas in Thailand: A survey assessment

Antimicrobial resistance (AMR), one of the major global threats to human security, has serious negative consequences for both health and economies. Excessive and inappropriate uses of antibiotics are the main drivers of the emergence of resistant bacterial strains. In Thailand, antibiotics have been used in citrus production since 2012 to treat citrus greening disease or Huanglongbing disease, despite no antibiotics being registered for use in mandarin. This raises concerns about irrational use of antibiotics, which can cause AMR