METHODS: Phylogenetic analysis was used to identify candidate Dendrobium catenatum R2R3-MYB (DcaMYB) sequences associated with pigment and cell shape development. Gene silencing of candidate DhMYBs in Dendrobium hybrid by direct application of dsRNA to developing flowers was followed by observation of gene expression level and flower phenotypes. Silencing of the structural gene chalcone synthase was used as a comparative control.

KEY RESULTS: Ten candidate flower-associated DcaMYBs were identified. Flowers treated with dsRNA of DhMYB22 and DhMYB60 sequences were less pigmented and had relatively low expression of anthocyanin biosynthetic genes (F3'H and DFR), lower total anthocyanin concentration and markedly lower levels of cyanidin-3-glucoside and cyanidin-3-rutinoside. Petals of DhMYB22-treated flowers and sepals of DhMYB60-treated flowers showed the greatest colour difference relative to the same organs in untreated flowers. DhMYB22-treated flowers had relatively narrow and constricted lips, while DhMYB60-treated flowers had narrow and constricted sepals. No significant difference in shape was observed for DhCHS-treated or untreated flowers.

METHOD: We assessed mental health and suicidal behavior of 102 self-identified homosexual males from a community-based organization that works with the sexual minority population.

RESULTS: One-third of the participants (32.4%) had experienced attempted suicide, and almost half (47.1%) had a history of suicidal ideation and self-harm (40.2%). Compared to a heterosexual sample, homosexual males had poorer mental health as they scored higher on Beck Hopelessness Scale (Cohen's d = 0.29) and General Health Questionnaire (GHQ) (Cohen's d = 0.57). The results revealed positive correlations between self-harm, suicidal ideation and suicide attempt scores. Participants with history of suicide attempt, suicide ideation and self-harm reported worse general health, more social dysfunction, and severe depression than those without such history.