MicroRNAs (miRNAs) are indispensable regulators for development and defense in eukaryotes. However, the miRNA species have not been explored for rice (Oryza sativa) immunity against the blast fungus Magnaporthe oryzae, the most devastating fungal pathogen in rice production worldwide. Here, by deep sequencing small RNA libraries from susceptible and resistant lines in normal conditions and upon M. oryzae infection, we identified a group of known rice miRNAs that were differentially expressed upon M. oryzae infection. They were further classified into three classes based on their expression patterns in the susceptible japonica line Lijiangxin Tuan Hegu and in the resistant line International Rice Blast Line Pyricularia-Kanto51-m-Tsuyuake that contains a single resistance gene locus, Pyricularia-Kanto 51-m (Pikm), within the Lijiangxin Tuan Hegu background. RNA-blot assay of nine of them confirmed sequencing results. Real-time reverse transcription-polymerase chain reaction assay showed that the expression of some target genes was negatively correlated with the expression of miRNAs. Moreover, transgenic rice plants overexpressing miR160a and miR398b displayed enhanced resistance to M. oryzae, as demonstrated by decreased fungal growth, increased hydrogen peroxide accumulation at the infection site, and up-regulated expression of defense-related genes. Taken together, our data indicate that miRNAs are involved in rice immunity against M. oryzae and that overexpression of miR160a or miR398b can enhance rice resistance to the disease.

Yield is majorly affected by photosynthetic efficiency. Leaves are essential structure for photosynthesis and their morphology especially size and shape in a plant canopy can affect the rate of transpiration, carbon fixation and photosynthesis. Leaf rolling and size are considered key agronomic traits in plant architecture that can subsidize yield parameters. In last era, a number of genes controlling leaf morphology have been molecularly characterized. Despite of several findings, our understanding toward molecular mechanism of leaf rolling and size are under-developed. Here, we proposed a model to apprehend the physiological basis of different genes organized in a complex fashion and govern the final phenotype of leaf morphology. According to this leaf rolling is mainly controlled by regulation of bulliform cells by SRL1, ROC5, OsRRK1, SLL2, CLD1, OsZHD1/2, and NRL1, structure and processes of sclerenchyma cells by SLL1 and SRL2, leaf polarity by ADL1, RFS and cuticle formation by CFL1, and CLD1. Many of above mentioned and several other genes interact in a complex manner in order to sustain cellular integrity and homeostasis for optimum leaf rolling. While, leaf size is synchronized by multifarious interaction of PLA1, PLA2, OsGASR1, and OsEXPA8 in cell division, NAL1, NAL9, NRL1, NRL2 in regulation of number of veins, OsCOW1, OsPIN1, OsARF19, OsOFP2, D1 and GID in regulation of phytohormones and HDT702 in epigenetic aspects. In this review, we curtailed recent advances engrossing regulation and functions of those genes that directly or indirectly can distress leaf rolling or size by encoding different types of proteins and genic expression. Moreover, this effort could be used further to develop comprehensive learning and directing our molecular breeding of rice.

Circadian clock, an endogenous time-setting mechanism, allows plants to adapt to unstable photoperiod conditions and induces flowering with proper timing. In Arabidopsis, the central clock oscillator was formed by a series of interlocked transcriptional feedback loops, but little is known in rice so far. By MutMap technique, we identified the candidate gene OsLHY from a later flowering mutant lem1 and further confirmed it through genetic complementation, RNA interference knockdown, and CRISPR/Cas9-knockout. Global transcriptome profiling and expression analyses revealed that OsLHY might be a vital circadian rhythm component. Interestingly, oslhy flowered later under ≥12 h day length but headed earlier under ≤11 h day length. qRT-PCR results exhibited that OsLHY might function through OsGI-Hd1 pathway. Subsequent one-hybrid assays in yeast, DNA affinity purification qPCR, and electrophoretic mobility shift assays confirmed OsLHY could directly bind to the CBS element in OsGI promoter. Moreover, the critical day length (CDL) for function reversal of OsLHY in oslhy (11-12 h) was prolonged in the double mutant oslhy osgi (about 13.5 h), indicating that the CDL set by OsLHY was OsGI dependent. Additionally, the dual function of OsLHY entirely relied on Hd1, as the double mutant oslhy hd1 showed the same heading date with hd1 under about 11.5, 13.5, and 14 h day lengths. Together, OsLHY could fine-tune the CDL by directly regulating OsGI, and Hd1 acts as the final effector of CDL downstream of OsLHY. Our study illustrates a new regulatory mechanism between the circadian clock and photoperiodic flowering.