Revealing the role of CCoAOMT1: fine-tuning bHLH transcription factors for optimal anther development

The tapetum,a crucial innermost layer encompassing male reproductive cells within the anther wall,plays a pivotal role in normal pollen development.The transcription factors (TFs) bHLH010/089/091 redundantly facilitate the rapid nuclear accumulation of DYSFUNCTIONAL TAPETUM 1,a gatekeeper TF in the tapetum.Nevertheless,the regulatory mechanisms governing the activity of bHLH010/089/091 remain unknown.In this study,we reveal that caffeoyl coenzyme A O-methyltransferase 1 (CCoAOMT1) is a negative regulator affecting the nuclear localization and function of bHLH010 and bHLH089,probably through their K259 site.Our findings underscore that CCoAOMT1 promotes the nuclear export and degradation of bHLH010 and bHLH089.Intriguingly,elevated CCoAOMT1 expression resulted in defective pollen development,mirroring the phenotype observed in bhlh010 bhlh089 mutants.Moreover,our investigation revealed that the K259A mutation in the bHLH089 protein disrupted its translocation from the nucleus to the cytosol and impeded its degradation induced by CCoAOMT1.Importantly,transgenic plants with the probHLH089::bHLH089^(K259A)construct failed to rescue proper pollen development or gene expression in bhlh010 bhlh089 mutants.Collectively,these findings emphasize the need to maintain balanced TF homeostasis for male fertility.They firmly establish CCoAOMT1 as a pivotal regulator that is instrumental in achieving equilibrium between the induction of the tapetum transcriptional network and ensuring appropriate anther development.

A widely targeted metabolite modificomics strategy for modified metabolites identification in tomato

The structural and functional diversity of plant metabolites is largely created via chemical modification of a basic backbone.However,metabolite modifications in plants have still not been thoroughly investigated by metabolomics approaches.In this study,a widely targeted metabolite modificomics(WTMM)strategy was developed based on ultra-high performance liquid chromatography-quadrupole-linear ion trap(UHPLC-Q-Trap)and UHPLC-Q-Exactive-Orbitrap(UHPLC-QE-Orbitrap),which greatly improved the detection sensitivity and the efficiency of identification of modified metabolites.A metabolite modificomics study was carried out using tomato as a model,and over 34,000 signals with MS2 information were obtained from approximately 232 neutral loss transitions.Unbiased metabolite profiling was also performed by utilizing high-resolution mass spectrometry data to annotate a total of 2,118 metabolites with 125 modification types;of these,165 modified metabolites were identified in this study.Next,the WTMM database was used to assess diseased tomato tissues and 29 biomarkers were analyzed.In summary,the WTMM strategy is not only capable of large-scale detection and quantitative analysis of plant-modified metabolites in plants,but also can be used for plant biomarker development.