Genetic and Transcriptome Analyses of Callus Browning in Chaling Common Wild Rice (Oryza rufipogon Griff.).

Callus browning during tissue culture of indica rice is genotype dependent, thus limiting the application of genetic transformation for editing-assisted breeding and elucidation of gene function. Here, using 124 introgression lines (HCLs) derived from a cross between the indica rice 9311 and Chaling common wild rice and 2059 SNPs for single-point and interval analysis, we identified two major QTLs, qCBT7 on chromosome 7 and qCBT10 on chromosome 10, related to callus browning, explaining 8-13% of callus browning. Moreover, we performed RNA-seq of two introgression lines with low callus browning, HCL183 and HCL232, with Oryza. rufipogon introgression fragments on chromosomes 10 and 7, respectively. Three candidate genes (Os07g0620700, Os10g0361000, and Os10g0456800) with upregulation were identified by combining interval mapping and weighted gene coexpression network analysis using the DEGs. The qRT-PCR results of the three candidate genes were consistent with those of RNA-seq. The differentiation of indica and japonica subspecies Oryza. sativa and Oryza. rufipogon suggests that these candidate genes are possibly unique in Oryza. rufipogon. GO analyses of hub genes revealed that callus browning may be mainly associated with ethylene and hormone signaling pathways. The results lay a foundation for future cloning of qCBT7 or qCBT10 and will improve genetic transformation efficiency in rice.

Housing and Community Environments vs. Independent Mobility: Roles in Promoting Children's Independent Travel and Unsupervised Outdoor Play.

Children's independent mobility (CIM) has declined dramatically in recent decades despite its benefits in facilitating childhood development, promoting physical activity, and combating the obesity epidemic. This US-based study examines the impacts of housing and neighborhood environments on two modes of CIM-home-based independent travel to non-school destinations and unsupervised outdoor play-while considering personal and social factors. A bilingual parent/guardian survey was distributed to public elementary schools in Austin, Texas, asking about children's travel and play, housing and neighborhood environments, and personal and social factors. A Google Street View audit was conducted to capture additional housing-related information. Logistic regressions were used to predict CIM. For second to fifth graders (N = 525), less than two-thirds of the parents would allow children's independent travel to non-school destinations (62%) and unsupervised outdoor play (57.9%), with the majority limited to a short distance (five-minute walk) and a few destinations (e.g., friend's/relative's home). Stranger danger was a negative predictor and the presence of friend's/relative's home was a positive predictor for both modes of CIM. Quality of neighborhood environment was another positive correlate for independent travel to non-school destinations. Significant personal and social factors were also identified. Study findings demonstrated the impacts of physical environments on CIM and the potential of using relevant interventions to promote children's health and development.