NECK LEAF 1, a GATA type transcription factor, modulates organogenesis by regulating the expression of multiple regulatory genes during reproductive development in rice

In the monocot rice species Oryza sativa L., one of the most striking morphological processes during reproductive development is the concurrence of panicle development with the sequential elongation of upper internodes （UPIs）. To elucidate the underlying molecular mechanisms, we cloned the rice gene NECK LEAF 1 （NL1）, which when mutated results in delays in flowering time, smaller panicles with overgrown bracts and abnormal UPI elongation patterns. The NL1 gene encodes a GATA-type transcription factor with a single zinc finger domain, and its transcripts are de- tected predominantly in the bract primordia, which normally degenerate in the wild-type plants. Overexpression of NL1 in transgenic plants often gives rise to severe growth retardation, less vegetative phytomers and smaller leaves, suggesting that NL1 plays an important role in organ differentiation. A novel mutant allele of PLASTOCHRON1 （PLAD, a gene known to play a key role in regulating leaf initiation, was identified in this study. Genetic analysis demonstrated an interaction between nil and plal, with NL1 acting upstream of PLA1. The expression level and spatial pattern of PLA1 were found to be altered in the nil mutant. Furthermore, the expression of two regulators of flowering, Hd3a and OsMADS1, was also affected in the nil mutant. On the basis of these findings, we propose that NL1 is an intrinsic factor that modulates and coordinates organogenesis through regulating the expression of PLA1 and other regulatory genes during reproductive development in rice.

Tissue-specific transcriptomics reveals a central role of CcNST1 in regulating the fruit lignification pattern in Camellia chekiangoleosa,a woody oil-crop

Fruit lignification is of significant economic importance because it affects the quality of fruit and the production of seed oil.The specified lignification pattern in Camellia chekiangoleosa fruits plays critical roles in its seed oil yield,but little is known about how this lignification process is regulated.Here,we report on a comprehensive tissue-specific transcriptomics analysis conducted for C.chekiangoleosa fruit.By mining the differentially expressed genes,we found that lignin biosynthesis and transcriptional regulation pathways were significantly enriched in the lignified tissues.The homolog of NST-like transcription factor,CcNST1,was highly expressed in lignified seed coat and endocarp tissues;transgenic analyses of CcNST1 in Arabidopsis and hybrid poplar revealed the enhanced lignification levels of various tissues.Gene expression analysis of the transgenic lines uncovered potential downstream genes involved in the regulation of lignin biosynthesis.This work provides a valuable gene expression resource and identified the pivotal role of CcNST1 in regulating the lignin biosynthesis underlying fruit lignification.

PHOSPHATIDYLSERINE SYNTHASE1 is Required for Inflorescence Meristem and Organ Development in Arabidopsis

Phosphatidylserine （PS）, a quantitatively minor membrane phospholipid, is involved in many biological processes besides its role in membrane structure. One PS synthesis gene, PHOSPHATIDYLSERINE SYNTHASE1 （PSSl）, has been discovered to be required for microspore development in Arabidopsis thaliana L. but how PSS1 affects postembryonic development is still largely unknown. Here, we show that PSSl is also required for inflorescence meristem and organ development in Arabidopsis. Disruption of PSSI causes severe dwarfism, smaller lateral organs and reduced size of inflorescence meristem. Morphological and molecular studies suggest that both cell division and cell elongation are affected in the pssl-1 mutant. RNA in situ hybridization and promoter GUS analysis show that expression of both WUSCHEL （WUS） and CLA VA TA3 （CL V3） depend on PSS1. Moreover, the defect in meristem maintenance is recovered and the expression of WUS and CLV3 are restored in the pssl-1 clvl-1 double mutant. Both SHOOTSTEMLESS （STM） and BREVIPEDICELLUS （BP） are upregulated, and auxin distribution is disrupted in rosette leaves of pssl-1. However, expression of BP, which is also a regulator of internode development, is lost in the pssl-1 inflorescence stem. Our data suggest that PSS1 plays essential roles in inflorescence meristem maintenance through the WUS-CLV pathway, and in leaf and internode development by differentially regulating the class I KNOX genes.

Plant Biosystems Design Research Roadmap 1.0

Human life intimately depends on plants for food,biomaterials,health,energy,and a sustainable environment.Various plants have been genetically improved mostly through breeding,along with limited modification via genetic engineering,yet they are still not able to meet the ever-increasing needs,in terms of both quantity and quality,resulting from the rapid increase in world population and expected standards of living.A step change that may address these challenges would be to expand the potential of plants using biosystems design approaches.This represents a shift in plant science research from relatively simple trial-and-error approaches to innovative strategies based on predictive models of biological systems.Plant biosystems design seeks to accelerate plant genetic improvement using genome editing and genetic circuit engineering or create novel plant systems through de novo synthesis of plant genomes.From this perspective,we present a comprehensive roadmap of plant biosystems design covering theories,principles,and technical methods,along with potential applications in basic and applied plant biology research.We highlight current challenges,future opportunities,and research priorities,along with a framework for international collaboration,towards rapid advancement of this emerging interdisciplinary area of research.Finally,we discuss the importance of social responsibility in utilizing plant biosystems design and suggest strategies for improving public perception,trust,and acceptance.