Latest Issue
Issue 6 ， 2020
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Breeding crops by design for future agriculture
Abstract：Plant breeding is both the science and art of developing elite crop cultivars by creating and reassembling desirable inherited traits for human benefit. From the bulk selection of wild plants for cultivation during early civilization to Mendelian genetics and genomics-assisted breeding in modern society, breeding methodologies have evolved over the last thousand years. In the past few decades, the “Green Revolution” through breeding of semi-dwarf wheat and rice varieties, and the use of heterosis and transgenic crops have dramatically enhanced crop productivity and helped prevent widespread famine (Hickey et al., 2019). Integration of these technologies can significantly improve breeding efficiency in the development of super crop varieties (Li et al., 2018). For example, a hybrid cotton variety CCRI63 and six related hybrid varieties account for nearly 90% of cotton production in the Yangtze River Basin (Wan et al., 2017; Wang et al., 2018). These varieties have successfully combined high yield, good quality, and biotic stress tolerance through the integration of conventional breeding, hybrid and genetically modified organism (GMO) technologies (Lu et al., 2019; Ma et al., 2019; Song et al., 2019). Unfortunately, such technology integration is not practical for most staple food crops, including rice and wheat, because of social or technical restrictions. Furthermore, plant breeding is still labor-intensive and time-consuming, and conventional breeding remains the leading approach for the release of commercial crop varieties worldwide. This is especially true for breeding cultivars and hybrids with high yield, good quality, and resistance to biotic or abiotic stresses (Liu et al., 2015; Gu et al., 2016). New germplasm, knowledge, and breeding techniques are required to breed the next generation of crop varieties.Keywords：Plant breeding;Gene editing;Crop varieties;Future agriculture- 84
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Published：2022-01-05
Editorial
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Advances in studies on ion transporters involved in salt tolerance and breeding crop cultivars with high salt tolerance
Abstract：Soil salinity is a global major abiotic stress threatening crop productivity. In salty conditions, plants may suffer from osmotic, ionic, and oxidative stresses, resulting in inhibition of growth and development. To deal with these stresses, plants have developed a series of tolerance mechanisms, including osmotic adjustment through accumulating compatible solutes in the cytoplasm, reactive oxygen species (ROS) scavenging through enhancing the activity of anti-oxidative enzymes, and Na+/K+ homeostasis regulation through controlling Na+ uptake and transportation. In this review, recent advances in studies of the mechanisms of salt tolerance in plants are described in relation to the ionome, transcriptome, proteome, and metabolome, and the main factor accounting for differences in salt tolerance among plant species or genotypes within a species is presented. We also discuss the application and roles of different breeding methodologies in developing salt-tolerant crop cultivars. In particular, we describe the advantages and perspectives of genome or gene editing in improving the salt tolerance of crops.Keywords：Salinity;Osmotic stress;Ionic stress;Oxidative stress;Salt tolerance- 66
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Published：2022-01-05 -
Breeding for low cadmium accumulation cereals
Abstract：Cadmium (Cd) is an element that is nonessential and extremely toxic to both plants and human beings. Soil contaminated with Cd has adverse impacts on crop yields and threatens human health via the food chain. Cultivation of low-Cd cultivars has been of particular interest and is one of the most cost-effective and promising approaches to minimize human dietary intake of Cd. Low-Cd crop cultivars should meet particular criteria, including acceptable yield and quality, and their edible parts should have Cd concentrations below maximum permissible concentrations for safe consumption, even when grown in Cd-contaminated soil. Several low-Cd cereal cultivars and genotypes have been developed worldwide through cultivar screening and conventional breeding. Molecular markers are powerful in facilitating the selection of low-Cd cereal cultivars. Modern molecular breeding technologies may have great potential in breeding programs for the development of low-Cd cultivars, especially when coupled with conventional breeding. In this review, we provide a synthesis of low-Cd cereal breeding.Keywords：Cereals;Low Cd accumulation;Gene/quantitative trait locus (QTL) mapping;Breeding- 31
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Published：2022-01-05 -
Gene editing: an instrument for practical application of gene biology to plant breeding
Abstract：Plant breeding is well recognized as one of the most important means to meet food security challenges caused by the ever-increasing world population. During the past three decades, plant breeding has been empowered by both new knowledge on trait development and regulation (e.g., functional genomics) and new technologies (e.g., biotechnologies and phenomics). Gene editing, particularly by clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas) and its variants, has become a powerful technology in plant research and may become a game-changer in plant breeding. Traits are conferred by coding and non-coding genes. From this perspective, we propose different editing strategies for these two types of genes. The activity of an encoded enzyme and its quantity are regulated at transcriptional and post-transcriptional, as well as translational and post-translational, levels. Different strategies are proposed to intervene to generate gene functional variations and consequently phenotype changes. For non-coding genes, trait modification could be achieved by regulating transcription of their own or target genes via gene editing. Also included is a scheme of protoplast editing to make gene editing more applicable in plant breeding. In summary, this review provides breeders with a host of options to translate gene biology into practical breeding strategies, i.e., to use gene editing as a mechanism to commercialize gene biology in plant breeding.Keywords：Gene editing;Expression regulation;Novel allele;Trait development;Plant breeding- 107
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Published：2022-01-05
Review
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Effects of supplying silicon nutrient on utilization rate of nitrogen and phosphorus nutrients by rice and its soil ecological mechanism in a hybrid rice double-cropping system
Abstract：This study was conducted to reveal the effects of silicon (Si) application on nutrient utilization efficiency by rice and on soil nutrient availability and soil microorganisms in a hybrid rice double-cropping planting system. A series of field experiments were conducted during 2017 and 2018. The results showed that Si nutrient supply improved grain yield and the utilization rates of nitrogen (N) and phosphorus (P) to an appropriate level for both early and late plantings, reaching a maximum at 23.4 kg/ha Si. The same trends were found for the ratios of available N (AN) to total N (TN) and available P (AP) to total P (TP), the soil microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), microbial biomass phosphorus (MBP), and the ratios of MBN to TN and MBP to TP, at different levels of Si. Statistical analysis further revealed that Si application enhanced rice growth and increased the utilization rate of fertilizer due to an ecological mechanism, i.e., Si supply significantly increased the total amount of soil microorganisms in paddy soil compared to the control. This promoted the mineralization of soil nutrients and improved the availability and reserves of easily mineralized organic nutrients.Keywords：Silicon nutrient;Utilization rate of fertilizer;Ecological mechanism;Rice double-cropping system- 118
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Published：2022-01-05 -
Effect of resveratrol treatment on apoptosis and apoptotic pathways during boar semen freezing
Abstract：Resveratrol (3,5,4'-trihydroxystilbene, RSV) has been widely used in mammalian cells, but whether it can be used during freezing boar semen is still unknown. The effects of RSV treatment during boar semen freezing on its anti-freezing ability, apoptosis, and possible apoptotic pathways were observed in this study. Sperm motility, mitochondrial membrane potential (ΔΨm), adenosine triphosphate (ATP) content, terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL)-positive apoptotic state, and messenger RNA (mRNA) expression levels of apoptotic genes involved in different apoptotic pathways after freezing with or without RSV treatment were tested. The results showed that: (1) Compared with fresh sperm, the motility, normal acrosome rate, and plasma membrane integrity rate of frozen boar sperm decreased significantly (P<0.05), and RSV did not significantly increase the sperm motility (0.44 vs. 0.40, P>0.05), but it did significantly improve the normal acrosome rate (57.65% vs. 47.00%, P<0.05) and plasma membrane integrity rate (46.67% vs. 38.85%, P<0.05). (2) After freezing, most boar sperm showed low mitochondrial ΔΨm. RSV treatment could increase the rate of high mitochondrial ΔΨm of boar sperm. (3) RSV treatment significantly decreased reactive oxygen species (ROS) levels (58.65% vs. 88.41%, P<0.05) and increased the ATP content (0.49 μmol/L vs. 0.25 μmol/L, P<0.05) of boar sperm during freezing. (4) The apoptotic rate of the freezing group (80.41%) with TUNEL detection increased significantly compared to the fresh group (9.70%, P<0.05), and RSV treatment greatly decreased the apoptotic rate (68.32%, P<0.05). (5) Real-time polymerase chain reaction (RT-PCR) showed that not only the genes from the death receptor-mediated apoptotic pathway (tumor necrosis factor-α (TNF-α), Fas ligand (FasL), and Caspase-8), but also the genes from the mitochondria-mediated apoptotic pathway (manganese superoxide dismutase (MnSOD), B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), and Caspase-9) were both significantly changed after freezing. RSV treatment during freezing greatly changed their expression levels. Although RSV treatment during boar semen freezing did not significantly increase motility after thawing, it still played an efficient antioxidant role, which could enhance the mitochondrial function and decrease the apoptotic level induced by both the death receptor-and mitochondria-mediated apoptotic pathways.Keywords：Resveratrol (RSV);Boar semen freezing;Antioxidant;Mitochondrial function;Apoptotic pathway- 155
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Published：2022-01-05 -
Screening of miRNAs associated with lymph node metastasis in Her-2-positive breast cancer and their relationship with prognosis#
Abstract：The aim of this study was to identify some biomarkers for predicting lymph node metastasis and prognosis of human epidermal growth factor receptor 2 (Her-2)-positive breast cancer (BC). We analyzed correlations between microRNAs (miRNAs) and the prognosis of patients with BC based on data collected from The Cancer Genome Atlas (TCGA) database. The expression levels of miR-455, miR-143, and miR-99a were measured in clinical samples of Her-2-positive BC patients with different degrees of lymph node metastasis. We investigated the impacts of overexpressed miR-455 on the proliferation and invasiveness of MDA-MB-453 cells and measured its effects on the expression of long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) by quantitative real-time polymerase chain reaction (qRT-PCR). The expression of miR-455 was significantly and positively correlated to the prognosis and overall survival (OS) of the BC (P=0.028), according to TCGA information. The expression level of miR-455 was positively correlated with OS and relapse-free survival (RFS) of patients with Her-2-positive BC, and was negatively correlated with the number of metastatic lymph nodes (P<0.05). Transwell assay suggested that MDA-MB-453 cells became much less invasive (P<0.01) after being transfected with miR-455 mimics. During the qRT-PCR, the expression level of MALAT1 declined significantly after transfection (P<0.01). Overexpressed miR-455 significantly inhibited the proliferation and migration of MDA-MB-453 cells and the expression of MALAT1. We conclude that miR-455 may be a useful potential biomarker for forecasting lymph node metastasis and the prognosis of Her-2-positive BC patients. miR-455 may play an important role in lymph node metastasis of BC by interacting with MALAT1.Keywords：Breast cancer (BC);Human epidermal growth factor receptor 2 (Her-2);Lymphatic metastasis;MicroRNA (miRNA);Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1)- 128
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Published：2022-01-05
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