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Biomedical subjects

Jinsheng Lai

Publications and source records attributed to Jinsheng Lai.

6 recordsLinked to original sources

Transcriptional and phytohormonal regulation of positional ear development reveals yield strategies in maize.

Maize (Zea mays L.) is a vital global crop, contributing ∼37% of annual grain production. Enhancing yield per unit area is crucial for food security, yet research has primarily focused on single-ear traits, overlooking the regulation of double ears-a key determinant of prolificacy. While secondary ears drive yield variability under prolificacy-favoring conditions, the mechanisms governing ear formation across shoot positions remain poorly understood. Here, we performed high-resolution transcriptomic analysis of 66 samples from three ear types (primary, secondary and third) in maize inbred B73. We uncovered distinct hormonal developmental dynamics: strigolactone (SL) signaling genes, particularly SBP transcription factors, dominated in primary (I) ears, whereas ethylene-related genes (e.g., ZmEREB131, ZmACCO35) were enriched in third (III) ears. Functional validation confirmed that knockout of ZmEREB131 and ZmACCO35 accelerated development and elongated ears compared to wild-type, implicating ethylene (ETH) signaling in ear maturation arrest. Notably, SL inhibitor application synchronized primary and secondary ear development, boosting total yield by >20% without compromising primary ear performance. Our study elucidates the transcriptional networks underlying differential ear development and provides actionable strategies for yield improvement through targeted hormonal modulation. These findings advance the understanding of maize inflorescence biology and offer molecular tools for breeding high-yielding varieties.

RNA-seq

Synergistic engineering of Casδ nuclease for robust genome editing.

Casδ is a recently identified evolutionary transitional CRISPR system characterized by its compact size (~900 amino acids), broad temperature tolerance, and guidance by a short crRNA without the requirement of a tracrRNA. However, the low editing efficiency of Casδ in eukaryotic cells limits its application. Here, we have developed a hierarchical engineering strategy to improve the genome editing activity of Casδ-1, with optimization focused on enhancing its interactions with the crRNA, the protospacer adjacent motif (PAM) duplex, the single-stranded DNA substrate, and the RNA-DNA heteroduplex. Through this strategy, we successfully generated an activity-enhanced Casδ-1 variant, designated enCasδ, which harbors 9 amino acid substitutions that synergistically augment its editing efficiency. In human cell lines, enCasδ showed 1.3- to 29.3-fold higher editing activity than the wild-type Casδ-1 across ten tested genomic loci, with an average editing efficiency of 54.6%. In addition, enCasδ also mediated robust genome editing in maize; its editing efficiency increased by an average of 5.3-fold relative to Casδ-1, and reached up to an average of 80% at the TS4 and PSY1 loci in stable transgenic lines. The overall editing performance of enCasδ was comparable to that of Streptococcus pyogenes Cas9 (SpCas9) and other Cas12 nucleases. Collectively, enCasδ represents a highly optimized Casδ-1 variant that broadens the applicability of the Casδ CRISPR system and facilitates robust genome editing in both animal cells and plants.

Gene Editing

Distinct evolutionary trajectories of subgenomic centromeres in polyploid wheat.

BACKGROUND: Centromeres are crucial for precise chromosome segregation and maintaining genome stability during cell division. However, their evolutionary dynamics, particularly in polyploid organisms with complex genomic architectures, remain largely enigmatic. Allopolyploid wheat, with its well-defined hierarchical ploidy series and recent polyploidization history, serves as an excellent model to explore centromere evolution. RESULTS: In this study, we perform a systematic comparative analysis of centromeres in common wheat and its corresponding ancestral species, utilizing the latest comprehensive reference genome assembly available. Our findings reveal that wheat centromeres predominantly consist of five types of centromeric-specific retrotransposon elements (CRWs), with CRW1 and CRW2 being the most prevalent. We identify distinct evolutionary trajectories in the functional centromeres of each subgenome, characterized by variations in copy number, insertion age, and CRW composition. By utilizing CENH3-ChIP data across various ploidy levels, we uncover a series of CRW invasion events that have shaped the evolution of AA subgenome centromeres. Conversely, the evolutionary process of the DD subgenome centromeres involves their expansion from diploid to hexaploid wheat, facilitating adaptation to a larger genomic context. Integration of complete einkorn centromere assemblies and Aegilops tauschii pan-genomes further revealed subgenome-specific centromere evolutionary trajectories. By inclusion of synthetic hexaploid from S2-S3 generations, alongside 2x/6 × natural accessions, we demonstrate that DD subgenome centromere expansion represents a gradual evolutionary process rather than an immediate response to polyploidization. CONCLUSIONS: Our study provides a comprehensive landscape of centromere adaptation, evolution, and maturation, along with insights into how retrotransposon invasions drive centromere evolution in polyploid wheat.

Centromere

GT1 regulates maize sex determination by affecting the jasmonate pathway.

Maize (Zea mays L.) is a monoecious plant with male and female flowers physically separated on different inflorescences-the tassel and the ear. Maize sex determination is controlled by a series of complicated developmental signals. Here, we characterized an EMS-induced maize feminized tassel mutant,tasselsilk1 (tsk1), and identified GRASSY TILLERS1 (GT1) as the causative gene. Phenotypic analysis of tsk1 mutants revealed that pistils fail to abort in both the tassel and ear, resulting in long sterile silks in the tassel and the development of an extra small kernel from the lower floret in the ear. RNA-seq and CUT&Tag analysis indicated that GT1 functioned as a repressor for flower organ development by regulating the JA biosynthesis and signaling pathways, specifically by directly promoting the expression of TASSELSEED1 (TS1), ZmMYC2A, ZmMYC2B. Together, we identified a new allele of GT1 and proposed that GT1 functions through JA biosynthesis and signaling pathways to regulate sex determination in maize.

Zea mays