Preharvest UV-C Hormesis Induces Key Genes Associated With Homeostasis, Growth and Defense in Lettuce Inoculated With Xanthomonas campestris pv. vitians

Preharvest application of hormetic doses of ultraviolet-C (UV-C) generates beneficial effects in plants. In this study, within 1 week, four UV-C treatments of 0.4 kJ/m2 were applied to 3-week-old lettuce seedlings. The leaves were inoculated with a virulent strain of Xanthomonas campestris pv. vitians (Xcv) 48 h after the last UV-C application. The extent of the disease was tracked over time and a transcriptomic analysis was performed on lettuce leaf samples. Samples of lettuce leaves, from both control and treated groups, were taken at two different times corresponding to T2, 48 h after the last UV-C treatment and T3, 24 h after inoculation (i.e., 72 h after the last UV-C treatment). A significant decrease in disease severity between the UV-C treated lettuce and the control was observed on days 4, 8, and 14 after pathogen inoculation. Data from the transcriptomic study revealed, that in response to the effect of UV-C alone and/or UV-C + Xcv, a total of 3828 genes were differentially regulated with fold change (|log2-FC|) > 1.5 and false discovery rate (FDR) < 0.05. Among these, of the 2270 genes of known function 1556 were upregulated and 714 were downregulated. A total of 10 candidate genes were verified by qPCR and were generally consistent with the transcriptomic results. The differentially expressed genes observed in lettuce under the conditions of the present study were associated with 14 different biological processes in the plant. These genes are involved in a series of metabolic pathways associated with the ability of lettuce treated with hormetic doses of UV-C to resume normal growth and to defend themselves against potential stressors. The results indicate that the hormetic dose of UV-C applied preharvest on lettuce in this study, can be considered as an eustress that does not interfere with the ability of the treated plants to carry on a set of key physiological processes namely: homeostasis, growth and defense.

Amino acid profile and scores of some selected traditional diets commonly consumed in northwest zone, Nigeria

Background and aims: Amino acids composition of local and regional dietary proteins determines the protein quality. The study was aimed at evaluating amino acid profiles of some selected traditional diets commonly consumed in Jigawa (JG), Kano (KN) and Katsina (KT) States, Northwest Zone-Nigeria. Methods: The selected prepared diets (four per state) include; JG Tuwon masara using white maize served with Kuka soup (JG TMW SWKS), JG Tuwon masara using yellow maize served with Kuka soup (JG TMY SWKS), JG Danwake served with groundnut oil and pepper (JG Danwake SWGOP), JG Moimoi, KN Tuwon masara using white maize served with Kuka soup (KN TMW SWKS), KN Tuwon masara using yellow maize served with Kuka soup (KN TMY SWKS), KN rice and beans served with groundnut oil and pepper (KN Rice and Beans SWGOP), KN Danwake served with groundnut oil and pepper (KN Danwake SWGOP), KT Tuwon masara using white maize served with Kuka soup (KT TMW SWKS), KT Tuwon masara using yellow maize served with Kuka soup (KT TMY SWKS), KT Danwake served with groundnut oil and pepper (KT Danwake SWGOP) and KT Dambu. The preparations were dried and grounded into powdered form and analyzed using standard methods. Results: The amino acid profile of the diets consumed in the three states show higher content of total non-essential amino acids (NEAA) compared with essential amino acids (EAA). The amino acid score of the prepared diets though higher than the standard amino acid score by WHO/FAO/UNU (2007), may support the normal growth of all age groups except lysine. The limiting amino acid score was found to be either lysine or SAA (cysteine + methionine) in all the 3 states’ diets. Histidine was found to have the highest score in all the diets except in JG Moimoi and KN Danwake served with groundnut oil and pepper (SWGOP) respectively. The low levels of lysine and SAA in some of the diets may be due to low contents of these amino acids in the ingredients used. Conclusion: This study showed that, the amino acid score of the prepared diets though higher than the standard amino acid score established by WHO/FAO/UNU may support the normal growth of infants, children as well as adults except lysine. Keywords: traditional diets, amino acids, amino acid profile, amino acid score.

Clinical and Genetic Characteristics of COL2A1-Associated Skeletal Dysplasias in 60 Russian Patients: Part I

The significant variability in the clinical manifestations of COL2A1-associated skeletal dysplasias makes it necessary to conduct a clinical and genetic analysis of individual nosological variants, which will contribute to improving our understanding of the pathogenetic mechanisms and prognosis. We presented the clinical and genetic characteristics of 60 Russian pediatric patients with type II collagenopathies caused by previously described and newly identified variants in the COL2A1 gene. Diagnosis confirmation was carried out by new generation sequencing of the target panel with subsequent validation of the identified variants using automated Sanger sequencing. It has been shown that clinical forms of spondyloepiphyseal dysplasias predominate in childhood, both with more severe clinical manifestations (58%) and with unusual phenotypes of mild forms with normal growth (25%). However, Stickler syndrome, type I was less common (17%). In the COL2A1 gene, 28 novel variants were identified, and a total of 63% of the variants were found in the triple helix region resulted in glycine substitution in Gly-XY repeats, which were identified in patients with clinical manifestations of congenital spondyloepiphyseal dysplasia with varying severity, and were not found in Stickler syndrome, type I and Kniest dysplasia. In the C-propeptide region, five novel variants leading to the development of unusual phenotypes of spondyloepiphyseal dysplasia have been identified.

COE2 Is Required for the Root Foraging Response to Nitrogen Limitation

There are numerous exchanges of signals and materials between leaves and roots, including nitrogen, which is one of the essential nutrients for plant growth and development. In this study we identified and characterized the Chlorophyll A/B-Binding Protein (CAB) (named coe2 for CAB overexpression 2) mutant, which is defective in the development of chloroplasts and roots under normal growth conditions. The phenotype of coe2 is caused by a mutation in the Nitric Oxide Associated (NOA1) gene that is implicated in a wide range of chloroplast functions including the regulation of metabolism and signaling of nitric oxide (NO). A transcriptome analysis reveals that expression of genes involved in metabolism and lateral root development are strongly altered in coe2 seedlings compared with WT. COE2 is expressed in hypocotyls, roots, root hairs, and root caps. Both the accumulation of NO and the growth of lateral roots are enhanced in WT but not in coe2 under nitrogen limitation. These new findings suggest that COE2-dependent signaling not only coordinates gene expression but also promotes chloroplast development and function by modulating root development and absorption of nitrogen compounds.

The C2H2 transcription factor SsZFH1 regulates the size, number and development of apothecia in Sclerotinia sclerotiorum

Sclerotinia sclerotiorum is a notorious phytopathogenic, Ascomycota fungus with a host range of over 600 plant species worldwide. This homothallic, Leotiomycetes species reproduces sexually through a multicellular apothecium which produces and releases ascospores. These ascospores serve as the primary inoculum source for disease initiation in the majority of S. sclerotiorum disease cycles. The regulation of apothecium development for this pathogen and other apothecium-producing fungi remains largely unknown. Here, we report that a C2H2 transcription factor SsZFH1 (zinc finger homologous protein) is necessary for the proper development and maturation of sclerotia and apothecia in S. sclerotiorum and is required for the normal growth rate of hyphae. Furthermore, ΔSszfh1 strains exhibit decreased reactive oxygen species (ROS) accumulation in hyphae, increased melanin deposition and enhanced tolerance to H2O2 in the process of vegetative growth and sclerotia formation. Infection assays on common bean leaves, with thin cuticles, and soybean and tomato leaves, with thick cuticles, suggest that the deletion of Sszfh1 slows the mycelial growth rate, which in turn affect the expansion of leaf lesions. Collectively, our results provide novel insights into the fungal factor mediating maturation of apothecia with additional effects on hyphae and sclerotia development.

Duckweed roots are dispensable and are on a trajectory toward vestigiality

Duckweeds are morphologically simplified, free floating aquatic monocots comprising both rooted and rootless genera. This has led to the idea that roots in these species may be vestigial, but empirical evidence supporting this is lacking. Here we show that duckweed roots are no longer required for their ancestral role of nutrient uptake. Comparative analyses of nearly all rooted duckweed species revealed a highly reduced anatomy, with greater simplification in the more recently diverged genus Lemna. A series of root excision experiments demonstrated that roots are dispensable for normal growth in Spirodela polyrhiza and Lemna minor. Furthermore, ionomic analyses of fronds in these two species showed little difference in the elemental composition of plants in rooted versus root-excised samples. In comparison, another free-floating member of the Araceae, Pistia stratiotes, which colonized the aquatic environment independently of duckweeds, has retained a more complex root anatomy. Whilst Pistia roots were not absolutely required for growth, their removal inhibited plant growth and resulted in a broad change in the mineral profile of aerial tissues. Collectively, these observations suggest that duckweeds and Pistia may be different stages along a trajectory towards root vestigialisation Given this, along with the striking diversity of root phenotypes, culminating in total loss in the most derived species, we propose that duckweed roots are a powerful system with which to understand organ loss and vestigiality.

Targeted deletion of liver-expressed Choriogenin L results in the production of soft eggs and infertility in medaka, Oryzias latipes

Egg envelopes (chorions) in medaka, Oryzias latipes, are composed of three major glycoproteins: ZI-1, − 2, and − 3. These gene-encoded chorion glycoproteins are expressed in the liver and/or ovarian oocytes of sexually mature female fish. In medaka, the glycoproteins produced in the female liver are induced by estrogen as Choriogenin (Chg.) H and Chg. H minor (m), which correspond to the zona pellucida (ZP) B (ZPB) protein in mammals, and Chg. L, which corresponds to ZPC in mammals. Chg. H, Chg. Hm, and Chg. L, are then converted to ZI-1, − 2, and − 3, respectively, during oogenesis in medaka ovaries.In the present study, we established a medaka line in which the chg.l gene was inactivated using the transcription activator-like effector nuclease (TALEN) technique. Neither intact chg.l transcripts nor Chg. L proteins were detected in livers of sexually mature female homozygotes for the mutation (homozygous chg.l knockout: chg.l−/−). The chg.l−/− females spawned string-like materials containing “smashed eggs.” Closer examination revealed the oocytes in the ovaries of chg.l−/− females had thin chorions, particularly at the inner layer, despite a normal growth rate. In comparing chorions from normal (chg.l+/+) and chg.l−/− oocytes, the latter exhibited abnormal architecture in the chorion pore canals through which the oocyte microvilli pass. These microvilli mediate the nutritional exchange between the oocyte and surrounding spaces and promote sperm-egg interactions during fertilization. Thus, following in vitro fertilization, no embryos developed in the artificially inseminated oocytes isolated from chg.l−/− ovaries. These results demonstrated that medaka ZI-3 (Chg.L) is the major component of the inner layer of the chorion, as it supports and maintains the oocyte’s structural shape, enabling it to withstand the pressures exerted against the chorion during spawning, and is essential for successful fertilization. Therefore, gene products of oocyte-specific ZP genes that may be expressed in medaka oocytes cannot compensate for the loss Chg. L function to produce offspring for this species.

Dephosphorylation of Nitrate Reductase Protein Regulates Growth of Rice and Adaptability to Low Temperature

Nitrate reductase (NR) is an important enzyme for nitrate assimilation in plants, and its activity is regulated by post-translational phosphorylation. To investigate the effect of NIA1 protein dephosphorylation on the growth of rice and its adaptability to low temperature, we analyzed phenotype, chlorophyll content, nitrogen utilization, and antioxidant capacity at low temperature in lines with a mutated NIA1 phosphorylation site (S532D and S532A), an OsNia1 over-expression line (OE), and wild-type Kitaake rice (WT). Plant height, dry matter weight, and chlorophyll content of S532D and S532A were lower than those of WT and OE under normal growth conditions but were higher than those of WT and OE at low temperature. Compared with WT and OE, the nitrite, H2O2, and MDA contents of S532D and S532A leaves were higher under normal growth conditions. The difference in leaf nitrite content between transgenic lines and WT was narrower at low temperature, especially in S532D and S532A, while H2O2 and MDA contents of S532D and S532A leaves were lower than those in WT and OE leaves. The NH4+-N and amino acid contents of S532D and S532A leaves were higher than those of WT and OE leaves under normal or low temperature. qRT-PCR results revealed that transcription levels of OsNrt2.4, OsNia2, and OsNADH-GOGAT were positively correlated with those of OsNia1, and the transcription levels of OsNrt2.4, OsNia2, and OsNADH-GOGAT were significantly higher in transgenic lines than in WT under both normal and low temperature. Phosphorylation of NR is a steady-state regulatory mechanism of nitrogen metabolism, and dephosphorylation of NIA1 protein improved NR activity and nitrogen utilization efficiency in rice. Excessive accumulation of nitrite under normal growth conditions inhibits the growth of rice; however, accumulation of nitrite is reduced at low temperature, enhancing the cold tolerance of rice.

Prenatal murine skeletogenesis partially recovers from absent skeletal muscle as development progresses

Skeletal muscle contractions are critical for normal growth and morphogenesis of the skeleton, but it is unclear how the detrimental effects of absent muscle on the bones and joints change over time. Joint size, shape and cavitation, and rudiment length and mineralisation were assessed in multiple rudiments at two developmental stages (Theiler Stage (TS)24 and TS27) in the splotch-delayed 'muscleless limb' mouse model and littermate controls. As development progressed, the effects of absent muscle on all parameters except for cavitation become less severe. All major joints in muscleless limbs were qualitatively and quantitatively abnormal in shape at TS24, while, by TS27, most muscleless joint shapes were normal, or nearly normal. In contrast, any joints which were fused at TS24 did not cavitate by TS27. Therefore, recovery in joint shape over development occurred despite absent cavitation. Mineralisation showed the most pronounced changes between TS24 and TS27 in the muscleless limbs. At TS24, all muscleless rudiments studied had less mineralisation than the controls, while at TS27, muscleless limb rudiments had either the same or significantly more mineralisation than controls of the same age. We conclude that the effects of absent muscle on prenatal murine skeletogenesis are most pronounced in early skeletal development and reduce in severity prior to birth. Understanding how mammalian bones and joints continue to develop in an environment without muscle contractions, but with mechanical stimulation due to the movement of the mother, provides important insights into conditions affecting human babies such as developmental dysplasia of the hip and arthrogryposis.