Integration of mRNA and miRNA analysis reveals the molecular mechanisms of sugar beet (Beta vulgaris L.) response to salt stress.

The continuous increase of saline-alkali areas worldwide has led to the emergence of saline-alkali conditions, which are the primary abiotic stress or hindering the growth of plants. Beet is among the main sources of sugar, and its yield and sugar content are notably affected by saline-alkali stress. Despite sugar beet being known as a salt-tolerant crop, there are few studies on the mechanisms underlying its salt tolerance, and previous studies have mainly delineated the crop's response to stress induced by NaCl. Recently, advancements in miRNA-mRNA network analysis have led to an increased understanding of how plants, including sugar beet, respond to stress. In this study, seedlings of beet variety "N98122" were grown in the laboratory using hydroponics culture and were exposed to salt stress at 40 days of growth. According to the phenotypic adaptation of the seedlings' leaves from a state of turgidity to wilting and then back to turgidity before and after exposure, 18 different time points were selected to collect samples for analysis. Subsequently, based on the data of real-time quantitative PCR (qRT-PCR) of salt-responsive genes, the samples collected at the 0, 2.5, 7.5, and 16 h time points were subjected to further analysis with experimental materials. Next, mRNA-seq data led to the identification of 8455 differentially expressed mRNAs (DEMs) under exposure to salt stress. In addition, miRNA-seq based investigation retrieved 3558 miRNAs under exposure to salt stress, encompassing 887 known miRNAs belonging to 783 families and 2,671 novel miRNAs. With the integrated analysis of miRNA-mRNA network, 57 miRNA-target gene pairs were obtained, consisting of 55 DEMIs and 57 DEMs. Afterwards, we determined the pivotal involvement of aldh2b7, thic, and δ-oat genes in the response of sugar beet to the effect of salt stress. Subsequently, we identified the miRNAs novel-m035-5p and novel-m0365-5p regulating the aldh gene and miRNA novel-m0979-3p regulating the thic gene. The findings of miRNA and mRNA expression were validated by qRT-PCR.

Association analysis of agronomic traits and construction of genetic networks by resequencing of 306 sugar beet (Beta vulgaris L.) lines.

Due to the relatively brief domestication history of sugar beet (Beta vulgaris ssp. vulgaris), our understanding of the genomic diversity and functional genes in its cultivars is limited, resulting in slow breeding progress. To address this issue, a total of 306 germplasm materials of major cultivars and breeding lines from China, the USA, and Europe were selected for genome resequencing. We investigated population structure and genetic diversity and performed selective scanning of genomic regions, identifying six novel genes associated with important agronomic traits: the candidate genes DFAX2 and P5CS for skin roughness; the candidate genes FRO5, GL24, and PPR91 for root yield and sugar yield, and the pleiotropic candidate gene POLX for flourishing growth vigour, plant height, crown size, flesh coarseness, and sugar yield. In addition, we constructed a protein-protein interaction network map and a phenotype-gene network map, which provide valuable information for identifying and characterizing functional genes affecting agronomic traits in sugar beet. Overall, our study sheds light on the future improvement of sugar beet agronomic traits at the molecular level.

Effects of Tai Chi versus Proprioception Exercise Program on Neuromuscular Function of the Ankle in Elderly People: A Randomized Controlled Trial.

Background. Tai Chi is a traditional Chinese medicine exercise used for improving neuromuscular function. This study aimed to investigate the effects of Tai Chi versus proprioception exercise program on neuromuscular function of the ankle in elderly people. Methods. Sixty elderly subjects were randomly allocated into three groups of 20 subjects per group. For 16 consecutive weeks, subjects participated in Tai Chi, proprioception exercise, or no structured exercise. Primary outcome measures included joint position sense and muscle strength of ankle. Subjects completed a satisfaction questionnaire upon study completion in Tai Chi and proprioception groups. Results. (1) Both Tai Chi group and proprioception exercise group were significantly better than control group in joint position sense of ankle, and there were no significant differences in joint position sense of ankle between TC group and PE group. (2) There were no significant differences in muscle strength of ankle among groups. (3) Subjects expressed more satisfaction with Tai Chi than with proprioception exercise program. Conclusions. None of the outcome measures on neuromuscular function at the ankle showed significant change posttraining in the two structured exercise groups. However, the subjects expressed more interest in and satisfaction with Tai Chi than proprioception exercise.