Cadmium (Cd) accumulation in rice grain poses a serious threat to human health. While several transport systems have been reported, the complexity of rice Cd transport and accumulation indicates the necessity of identifying additional genes, especially those that are responsible for Cd accumulation divergence between indica and japonica rice subspecies. Here, we show that a gene, OsCd1 , belonging to the major facilitator superfamily is involved in root Cd uptake and contributes to grain accumulation in rice. Natural variation in OsCd1 with a missense mutation Val449Asp is responsible for the divergence of rice grain Cd accumulation between indica and japonica . Near-isogenic line tests confirm that the indica variety carrying the japonica allele OsCd1 V449 can reduce the grain Cd accumulation. Thus, the japonica allele OsCd1 V449 may be useful for reducing grain Cd accumulation of indica rice cultivars through breeding.

Background and aims Previous studies on smartphone use motivation (SUM) and problematic smartphone use (PSU) have been limited in the utilization of regional samples of emerging adults (e.g., college students) and also in the foci on the direct association between SUM and PSU. To address such gaps, using data from a large, national representative sample of Chinese young adolescents and their parents this study examined the associations between adolescents' various types of SUM and their PSU, and also tested the potential mediating roles of smartphone use time (SUT) that adolescents spent on various activities in such associations. Methods A nationwide representative sample of 8,261 Chinese adolescents (Mage = 12.86 years old, SD = 1.76; 42.6% females) and their parents (49% mothers) participated in this survey study. Results Instrumental SUM (i.e., to expand knowledge or acquire information) was associated negatively with PSU via longer SUT spent on learning and shorter SUT spent on entertainment and communication. Self-expression SUM (i.e., to gain acceptance and recognition of others by maintaining or improving self-images) was associated with longer SUT spent on both learning and entertainment, which, in turn, predicted lower and higher levels of PSU, respectively. Last, hedonic SUM (i.e., to gain pleasure) was associated positively with PSU via longer SUT spent on entertainment and communication. Discussion These findings contribute to the literature by adding greater specificity in our understanding of the implications of SUM and SUT in the etiology of PSU during the critical life stage of adolescence in a Chinese cultural context.

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