Expansins are cell wall loosening proteins which generally play important roles as endogenous regulators in plants. Here we report a rice (Oryza sativa L.) b-expansin gene, OsEXPB2, which encodes a 28.6-kDa protein of 261 amino acids. Sequence alignment revealed that the N-terminal and C-terminal of OsEXPB2 share six discontinuous cysteine residues and four intermittent tryptophan residues, respectively. The OsEXPB2 promoter contains conserved root hair-specific elements. Subcellular localization assay revealed that OsEXPB2 was localized in the cell wall. Analysis of spatial and temporal expression patterns demonstrated that OsEXPB2 was predominantly expressed in root of rice. OsEXPB2 expression levels were up-regulated by abiotic stresses, such as phosphate or iron deficiency, and also suppressed by abscisic acid. A clear difference was observed between RNA interference (RNAi) lines and wildtype in root system architecture and plant height, and the suppression of OsEXPB2 resulted in a visible alteration of the width of the leaf blade. Anatomical analysis found that the cell size of root cortical cells in OsEXPB2-suppressed lines was significantly smaller than that of their counterparts in wild-type plants. Furthermore, cryo-scanning electron microscopy analysis showed that the development of root hair was suppressed in RNAi lines. All these results suggest that OsEXPB2 is a root-predominant gene with a key role in root-hair formation and has the potential to be utilized in transgenic root breeding to improve abiotic stress tolerance.

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DEETIOLATED1 (DET1) plays a critical role in developmental and environmental responses in many plants. To date, the functions of OsDET1 in rice (Oryza sativa) have been largely unknown. OsDET1 is an ortholog of Arabidopsis (Arabidopsis thaliana) DET1. Here, we found that OsDET1 is essential for maintaining normal rice development. The repression of OsDET1 had detrimental effects on plant development, and leaded to contradictory phenotypes related to abscisic acid (ABA) in OsDET1 interference (RNAi) plants. We found that OsDET1 is involved in modulating ABA signaling in rice. OsDET1 RNAi plants exhibited an ABA hypersensitivity phenotype. Using yeast two-hybrid (Y2H) and bimolecular fluorescence complementation assays, we determined that OsDET1 interacts physically with DAMAGED-SPECIFIC DNA-BINDING PROTEIN1 (OsDDB1) and CONSTITUTIVE PHOTOMORPHOGENIC10 (COP10); DET1-and DDB1-ASSOCIATED1 binds to the ABA receptors OsPYL5 and OsDDB1. We found that the degradation of OsPYL5 was delayed in OsDET1 RNAi plants. These findings suggest that OsDET1 deficiency disturbs the COP10-DET1-DDB1 complex, which is responsible for ABA receptor (OsPYL) degradation, eventually leading to ABA sensitivity in rice. Additionally, OsDET1 also modulated ABA biosynthesis, as ABA biosynthesis was inhibited in OsDET1 RNAi plants and promoted in OsDET1-overexpressing transgenic plants. In conclusion, our data suggest that OsDET1 plays an important role in maintaining normal development in rice and mediates the cross talk between ABA biosynthesis and ABA signaling pathways in rice.

Objective: Parental psychopathology is a significant risk factor for mental health challenges in offspring, but the nature and magnitude of this link in Indigenous Peoples is not well understood. This systematic review examined the emotional and behavioral functioning of the offspring of Indigenous parents with mental health challenges. Method: We searched MEDLINE, EMBASE, PsycINFO, CINAHL, and Web of Science from their inceptions until April 2020. Studies were included if they included assessments of emotional, behavioral, or other psychological outcomes in the offspring of Indigenous parents with a mental health challenge. Results: The 14 studies eligible for review were focused on parental substance misuse ( n = 8), maternal internalizing (i.e., depression, anxiety) issues ( n = 5), and poor overall parental mental health ( n = 4). In 11 studies, parental substance misuse, depression, and/or overall mental health challenges were associated with 2 to 4 times the odds of offspring externalizing and internalizing behaviors as compared to offspring of Indigenous parents without mental health challenges. Conclusion: The findings suggest higher risks of mental health challenges among offspring of Indigenous parents with psychiatric difficulties than among Indigenous children of parents without similar difficulties. Knowledge of these phenomena would be improved by the use of larger, more representative samples, culturally appropriate measures, and the engagement of Indigenous communities. Future studies should be focused on both risk and resilience mechanisms so that cycles of transmission can be interrupted and resources aimed at detection, prevention, and treatment optimally allocated.