Endoplasmic reticulum calnexins participate in the primary root growth response to phosphate deficiency

Insights into cucumber (Cucumis sativus) genetics: Genome-wide discovery and computational analysis of the Calreticulin Domain-Encoding gene (CDEG) family

Cucumber is an essential vegetable crop throughout the world. Cucumber development is vital for accomplishing both quality and productivity requirements. Meanwhile, numerous factors have resulted in substantial cucumber losses. However, the calreticulin domain-encoding genes (CDEGs) in cucumber were not well-characterized and had little function. In the genome-wide association study (GWAS), we recognized and characterized the CDEGs in Cucumis sativus (cucumber). Through a comprehensive study of C. sativus, our research has unveiled the presence of three unique genes, denoted as CsCRTb, CsCRT3, and CsCNX1, unevenly distributed on three chromosomes in the genome of C. sativus. In accordance to the phylogenetic investigation, these genes may be categorized into three subfamilies. Based on the resemblance with AtCDE genes, we reorganized the all CsCDE genes in accordance with international nomenclature. The expression analysis and cis-acting components revealed that each of CsCDE gene promoter region enclosed number of cis-elements connected with hormone and stress response. According to subcellular localization studies demonstrated that, they were found in deferent locations of the cell such as endoplasmic reticulum, plasma membrane, golgi apparatus, and vacuole, according to subcellular localization studies. Chromosomal distribution analysis and synteny analysis demonstrated the probability of segmental or tandem duplications within the cucumber CDEG gene family. Additionally, miRNAs displayed diverse modes of action, including mRNA cleavage and translational inhibition. We used the RNA seq data to analyze the expression of CDEG genes in response to cold stress and also improved cold tolerance, which was brought on by treating cucumber plants to an exogenous chitosan oligosaccharide spray. Our investigation revealed that these genes responded to this stress in a variety of ways, demonstrating that they may adapt quickly to environmental changes in cucumber plants. This study provides a base for further understanding in reference to CDE gene family and reveals that genes play significant functions in cucumber stress responses.

Long noncoding RNA TRABA suppresses β-glucosidase-encoding BGLU24 to promote salt tolerance in cotton

Salt stress severely damages the growth and yield of crops. Recently, long noncoding RNAs (lncRNAs) were demonstrated to regulate various biological processes and responses to environmental stresses. However, the regulatory mechanisms of lncRNAs in cotton (Gossypium hirsutum) response to salt stress are still poorly understood. Here, we observed that a lncRNA, trans acting of BGLU24 by lncRNA (TRABA), was highly expressed while GhBGLU24-A was weakly expressed in a salt-tolerant cotton accession (DM37) compared to a salt-sensitive accession (TM-1). Using TRABA as an effector and proGhBGLU24-A-driven GUS as a reporter, we showed that TRABA suppressed GhBGLU24-A promoter activity in double transgenic Arabidopsis (Arabidopsis thaliana), which explained why GhBGLU24-A was weakly expressed in the salt-tolerant accession compared to the salt-sensitive accession. GhBGLU24-A encodes an endoplasmic reticulum (ER)-localized β-glucosidase that responds to salt stress. Further investigation revealed that GhBGLU24-A interacted with RING-type E3 ubiquitin ligase (GhRUBL). Virus-induced gene silencing (VIGS) and transgenic Arabidopsis studies revealed that both GhBGLU24-A and GhRUBL diminish plant tolerance to salt stress and ER stress. Based on its substantial effect on ER-related degradation (ERAD)-associated gene expression, GhBGLU24-A mediates ER stress likely through the ERAD pathway. These findings provide insights into the regulatory role of the lncRNA TRABA in modulating salt and ER stresses in cotton and have potential implications for developing more resilient crops.

A CYBDOM protein impacts iron homeostasis and primary root growth under phosphate deficiency in Arabidopsis

Arabidopsis primary root growth response to phosphate (Pi) deficiency is mainly controlled by changes in apoplastic iron (Fe). Upon Pi deficiency, apoplastic Fe deposition in the root apical meristem activates pathways leading to the arrest of meristem maintenance and inhibition of cell elongation. Here, we report that a member of the uncharacterized cytochrome b561 and DOMON domain (CYBDOM) protein family, named CRR, promotes iron reduction in an ascorbate-dependent manner and controls apoplastic iron deposition. Under low Pi, the crr mutant shows an enhanced reduction of primary root growth associated with increased apoplastic Fe in the root meristem and a reduction in meristematic cell division. Conversely, CRR overexpression abolishes apoplastic Fe deposition rendering primary root growth insensitive to low Pi. The crr single mutant and crr hyp1 double mutant, harboring a null allele in another member of the CYDOM family, shows increased tolerance to high-Fe stress upon germination and seedling growth. Conversely, CRR overexpression is associated with increased uptake and translocation of Fe to the shoot and results in plants highly sensitive to Fe excess. Our results identify a ferric reductase implicated in Fe homeostasis and developmental responses to abiotic stress, and reveal a biological role for CYBDOM proteins in plants.

A Plate Growth Assay to Quantify Embryonic Root Development of Zea mays

Murashige-Skoog medium solutions have been used in a variety of plant plate growth assays, yet most research uses Arabidopsis thaliana as the study organism. For larger seeds such as maize (Zea mays), most protocols employ a paper towel roll method for experiments, which often involves wrapping maize seedlings in wet, sterile germination paper. What the paper towel roll method lacks, however, is the ability to image the roots over time without risk of contamination. Here, we describe a sterile plate growth assay that contains Murashige-Skoog medium to grow seedlings starting two days after germination. This protocol uses a section of a paper towel roll method to achieve uniform germination of maize seedlings, which are sterilely transferred onto large acrylic plates for the duration of the experiment. The media can undergo modification to include an assortment of plant hormones, exogenous sugars, and other chemicals. The acrylic plates allow researchers to freely image the plate without disturbing the seedlings and control the environment in which the seedlings are grown, such as modifications in temperature and light. Additionally, the protocol is widely adaptable for use with other cereal crops. Key features • Builds upon plate growth methods routinely used for Arabidopsis seedlings but that are inadequate for maize. • Real-time photographic analysis of seedlings up to two weeks following germination. • Allows for testing of various growth conditions involving an assortment of additives and/or modification of environmental conditions. • Samples are able to be collected for genotype screening.