Integrating advancements in root phenotyping and genome-wide association studies to open the root genetics gateway.

Plant adaptation to challenging environmental conditions around the world has made root growth and development an important research area for plant breeders and scientists. Targeted manipulation of root system architecture (RSA) to increase water and nutrient use efficiency can minimize the adverse effects of climate change on crop production. However, phenotyping of RSA is a major bottleneck since the roots are hidden in the soil. Recently the development of 2- and 3D root imaging techniques combined with the genome-wide association studies (GWASs) have opened up new research tools to identify the genetic basis of RSA. These approaches provide a comprehensive understanding of the RSA, by accelerating the identification and characterization of genes involved in root growth and development. This review summarizes the latest developments in phenotyping techniques and GWAS for RSA, which are used to map important genes regulating various aspects of RSA under varying environmental conditions. Furthermore, we discussed about the state-of-the-art image analysis tools integrated with various phenotyping platforms for investigating and quantifying root traits with the highest phenotypic plasticity in both artificial and natural environments which were used for large scale association mapping studies, leading to the identification of RSA phenotypes and their underlying genetics with the greatest potential for RSA improvement. In addition, challenges in root phenotyping and GWAS are also highlighted, along with future research directions employing machine learning and pan-genomics approaches.

Overexpression of GhKTI12 Enhances Seed Yield and Biomass Production in Nicotiana Tabacum.

Crop molecular breeding primarily focuses on increasing the trait of plant yield. An elongator-associated protein, KTI12, is closely associated with plant biomass and yield. KTI12 is involved in developmental processes of most organs, including the leaf, root, flower, and seed, through regulating cell division and differentiation. Previous work has shown that in upland cotton (Gossypium hirsutum), GhKTI12 regulates plant height, flowering, and tolerance to salt and drought stress. However, little is known about the molecular regulation mechanism of GhKTI12 in plant developmental processes. In this study, we identified the main GhKTI12 (Gh_D02G144400) gene and transformed it into tobacco (Nicotonia tabacum cv NC89). From seven transgenic lines, we obtained three (OE5, OE6 and OE8) with high expression of GhKTI12; compared with wild type plants, these three lines exhibited larger plant size, later flowering, and higher seed yield. Microscopic observation revealed that the number of leaf epidermal cells and stem parenchyma cells was increased by ~55%. Biochemical analysis showed that chlorophyll content and starch accumulation were significantly increased in younger leaves at the top canopy of transgenic plants, which may contribute to improved photosynthetic rate and, in turn, increased seed yield. To understand the molecular mechanism of GhKTI12 in transgenic plants development, two lines (OE6 and OE8) with higher expression levels of GhKTI12 were used as representative plants to conduct RNA-seq analysis. Through transcriptome analysis of the plant's shoot apical meristematic tissue of these two lines, we identified 518 upregulated genes and 406 downregulated genes common to both overexpression lines. A large number of cellular component genes associated with cell division and differentiation, such as RD21, TET8, KTN80, AOX1, AOX2, CP1, and KIC, were found to be upregulated, and genes showing the most downregulation included MADS-box genes related to flowering time, such as MADS6, AP1, AP3, AGL8, AGL6, SEP1, and SEP2. Downregulation of these genes caused delayed flowering time and longer vegetative stage during development. Combined with the upregulation of the yield-related gene RD21, the GhKTI12 transgenic plants could produce a higher seed yield. We here show that the overexpression of GhKTI12 could positively improve key agronomic traits in tobacco by regulating cell proliferation, photosynthesis, and organ development, and suggest that homologs of GhKTI12 may also be important in the genetic improvement of other crop plants.

The assessment of environmental sustainability: The role of research and development in ASEAN countries.

Considering the set targets of the Association of Southeast Asian Nations (ASEAN) to increase research and development (R&D) expenditures, this study probes the long-term and causal association between renewable energy (RE), nonrenewable energy (NRE), economic growth (GDP), and ecological footprints (EFs) in the context of the environmental Kuznets curve (EKC). Empirical evidence is based on the panel data throughout the period 1990-2016 for the selected six ASEAN economies. The Westerlund co-integration test confirms the long-run association between R&D, RE, NRE, GDP, and EF. The results of Fully Modified Ordinary Least Squares (FMOLS) and Dynamic Ordinary Least Squares (DOLS) confirm the presence of EKC and show that R&D expenditures lower EF significantly. A 1% increase in R&D and RE decreases EF by 0.01% and 0.27%, respectively. Moreover, a 1% increase in GDP and NRE increases EF by 5.52% and 0.17%, respectively. This means that investment in R&D will enhance air quality by lowering EF in estimated panel countries. Moreover, NRE consumption and GDP increase EF. The panel causality results confirm the bidirectional association between GDP, RE use, R&D expenditures, and EF. To achieve a desirable goal of a clean environment, R&D expenditures hold a strong position for ASEAN countries. This finding should encourage governments to involve public and private investments in R&D programs for energy efficiency. Integr Environ Assess Manag 2022;18:1313-1320. © 2021 SETAC.

Correction: Syed, T., et al. Current Insights on Vegetative Insecticidal Proteins (Vip) as Next Generation Pest Killers. Toxins 2020, 12, 522.

The authors wish to make the following corrections to their paper [...].

Current Insights on Vegetative Insecticidal Proteins (Vip) as Next Generation Pest Killers.

Bacillus thuringiensis (Bt) is a Gram negative soil bacterium. This bacterium secretes various proteins during different growth phases with an insecticidal potential against many economically important crop pests. One of the important families of Bt proteins is vegetative insecticidal proteins (Vip), which are secreted into the growth medium during vegetative growth. There are three subfamilies of Vip proteins. Vip1 and Vip2 heterodimer toxins have an insecticidal activity against many Coleopteran and Hemipteran pests. Vip3, the most extensively studied family of Vip toxins, is effective against Lepidopteron. Vip proteins do not share homology in sequence and binding sites with Cry proteins, but share similarities at some points in their mechanism of action. Vip3 proteins are expressed as pyramids alongside Cry proteins in crops like maize and cotton, so as to control resistant pests and delay the evolution of resistance. Biotechnological- and in silico-based analyses are promising for the generation of mutant Vip proteins with an enhanced insecticidal activity and broader spectrum of target insects.

Genome-Wide Characterization and Expression Analysis of NHX Gene Family under Salinity Stress in Gossypium barbadense and Its Comparison with Gossypium hirsutum.

Cotton is an important economic crop affected by different abiotic stresses at different developmental stages. Salinity limits the growth and productivity of crops worldwide. Na+/H+ antiporters play a key role during the plant development and in its tolerance to salt stress. The aim of the present study was a genome-wide characterization and expression pattern analysis under the salinity stress of the sodium-proton antiporter (NHX) of Gossypium barbadense in comparison with Gossypium hirsutum. In G. barbadense, 25 NHX genes were identified on the basis of the Na+_H+ exchanger domain. All except one of the G. barbadenseNHX transporters have an Amiloride motif that is a known inhibitor of Na+ ions in plants. A phylogenetic analysis inferred three classes of GbNHX genes-viz., Vac (GbNHX1, 2 and 4), Endo (GbNHX6), and PM (GbNHX7). A high number of the stress-related cis-acting elements observed in promoters show their role in tolerance against abiotic stresses. The Ka/Ks values show that the majority of GbNHX genes are subjected to strong purifying selection under the course of evolution. To study the functional divergence of G. barbadenseNHX transporters, the real-time gene expression was analyzed under salt stress in the root, stem, and leaf tissues. In G. barbadense, the expression was higher in the stem, while in G. hirsutum the leaf and root showed a high expression. Moreover, our results revealed that NHX2 homologues in both species have a high expression under salinity stress at higher time intervals, followed by NHX7. The protein-protein prediction study revealed that GbNHX7 is involved in the CBL-CIPK protein interaction pathway. Our study also provided valuable information explaining the molecular mechanism of Na+ transport for the further functional study of Gossypium NHX genes.