About

Susheng Gan is a professor in the School of Integrative Plant Science, Plant Biology Section. His research focuses on the molecular regulatory mechanisms of plant senescence and the dimensional control of gene expression in plants. His work has significant implications for crop yields and postharvest storage, particularly in understanding and manipulating leaf yellowing and senescence processes. Gan employs various molecular, genetic, and genomic approaches to clone and analyze genes involved in senescence in Arabidopsis and tobacco plants. His ongoing projects include functional characterization of senescence-specific transcription factors, networking these factors, and developing cloning systems for senescence-inhibiting genes. Gan actively participates in outreach activities to demonstrate the importance of senescence research, the development of senescence-manipulating technologies, and their societal applications. His contributions extend to teaching courses related to plant senescence, postharvest biology, and plant cell and molecular biology, and he holds a doctorate from the University of Wisconsin-Madison.

Research topics

• Biology
• Botany
• Cell biology
• Endocrinology
• Genetics

Selected publications

• Somatic-to-germline transmission of horizontally acquired extrachromosomal circular DNA in Brassica graft chimeras

  bioRxiv (Cold Spring Harbor Laboratory) · 2026-05-12

  article

  Abstract Whether somatically acquired traits can contribute to heritable variation has remained an open question in plant biology for over a century. Here, using graft-induced periclinal chimeras between Brassica juncea and Brassica oleracea , we identified extrachromosomal circular DNA (eccDNA) as mobile genetic elements capable of crossing histological boundaries and entering the germline. We demonstrated that grafting could promote the horizontal transfer of eccDNA between somatic cell layers, enabling its stable maintenance in recipient tissues and permitting transmission through sexual reproduction across multiple generations. We found that transmitted eccDNA is non-randomly distributed across the genome, preferentially originating from gene-dense regions, and enriched for features associated with molecular persistence, such as inverted repeats, hairpin-forming sequences, and autonomously replicating sequence (ARS) consensus motifs. These genetic regions conferred replication competence, as evidenced by autonomous propagation in an ARS-less heterologous yeast system. Sexual progeny carrying graft-acquired eccDNA exhibited reproducible and lineage-dependent alterations in leaf morphology and drought tolerance, accompanied by coordinated transcriptional reprogramming. Notably, a subset of inherited eccDNA remained transcriptionally active in progeny, producing transcripts absent from self-grafted controls. Our findings establish eccDNA as heritable extrachromosomal elements that link graft-mediated somatic genetic transfer with stable germline transmission, thereby expanding the molecular scope of heritable variation in plants and providing a conceptual framework for graft-based trait transmission.

  PublisherDOI

• ER-related E2-E3 ubiquitin enzyme pair regulates ethylene response by modulating the turnover of ethylene receptors

  Nature Communications · 2025-07-01 · 10 citations

  articleOpen access

  Gaseous phytohormone ethylene regulates various aspects of plant development. Ethylene is perceived by ER membrane-localized receptors, which are inactivated upon binding with ethylene molecules, thereby initiating ethylene signal transduction. Here, we report that a novel E3 ligase RING finger for Ethylene receptor Degradation (RED) and its E2 partner UBC32 ubiquitinate ethylene-bound receptors for degradation through an ER associated degradation (ERAD) pathway in both Rosa hybrida and Solanum lycopersicum. The depletion of RED or UBC32 leads to hypersensitivity to ethylene, which is manifested as premature leaf abscission and petal shedding in roses, as well as the dwarf plants and accelerated fruit ripening in tomatoes. Disruption of the conserved ethylene binding site of receptors prevents RED-mediated degradation of the receptors. Our study discovers an ERAD branch that facilitates the ethylene-induced degradation of receptors, and provides insights into how the plant’s response to ethylene can be controlled by modulating the turnover of ethylene receptors. Zhao et al. identified a novel E3 ligase RED and its E2 partner UBC32 which mediates ethylene-induced degradation of ethylene receptors ETR3 via the ERAD pathway in Rosa hybrida and Solanum lycopersicum, providing new insights into controlling ethylene response through receptor turnover.

  PublisherOA PDFDOI

• Use of NAP gene to manipulate leaf senescence in plants

  OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information) · 2023-01-23

  articleOpen access1st authorCorresponding

  The present invention discloses transgenic plants having an altered level of NAP protein compared to that of a non-transgenic plant, where the transgenic plants display an altered leaf senescence phenotype relative to a non-transgenic plant, as well as mutant plants comprising an inactivated NAP gene, where mutant plants display a delayed leaf senescence phenotype compared to that of a non-mutant plant. The present invention also discloses methods for delaying leaf senescence in a plant, as well as methods of making a mutant plant having a decreased level of NAP protein compared to that of a non-mutant plant, where the mutant plant displays a delayed leaf senescence phenotype relative to a non-mutant plant. Methods for causing precocious leaf senescence or promoting leaf senescence in a plant are also disclosed. Also disclosed are methods of identifying a candidate plant suitable for breeding that displays a delayed leaf senescence and/or enhanced yield phenotype.

  PublisherOA PDF

• The ABA–AtNAP–SAG113 PP2C module regulates leaf senescence by dephoshorylating SAG114 SnRK3.25 in Arabidopsis

  Molecular Horticulture · 2023-10-30 · 10 citations

  articleOpen accessSenior author

  We previously reported that ABA inhibits stomatal closure through AtNAP-SAG113 PP2C regulatory module during leaf senescence. The mechanism by which this module exerts its function is unknown. Here we report the identification and functional analysis of SAG114, a direct target of the regulatory module. SAG114 encodes SnRK3.25. Both bimolecular fluorescence complementation (BiFC) and yeast two-hybrid assays show that SAG113 PP2C physically interacts with SAG114 SnRK3.25. Biochemically the SAG113 PP2C dephosphorylates SAG114 in vitro and in planta. RT-PCR and GUS reporter analyses show that SAG114 is specifically expressed in senescing leaves in Arabidopsis. Functionally, the SAG114 knockout mutant plants have a significantly bigger stomatal aperture and a much faster water loss rate in senescing leaves than those of wild type, and display a precocious senescence phenotype. The premature senescence phenotype of sag114 is epistatic to sag113 (that exhibits a remarkable delay in leaf senescence) because the sag113 sag114 double mutant plants show an early leaf senescence phenotype, similar to that of sag114. These results not only demonstrate that the ABA-AtNAP-SAG113 PP2C regulatory module controls leaf longevity by dephosphorylating SAG114 kinase, but also reveal the involvement of the SnRK3 family gene in stomatal movement and water loss during leaf senescence.

  PublisherOA PDFDOI

• Increasing leaf longevity and disease resistance by altering salicylic acid catabolism

  OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information) · 2023-01-23 · 2 citations

  articleOpen access1st authorCorresponding

  The present invention relates to a transgenic plant having an altered level of salicylic acid 3-hydroxylase ("S3H") protein, compared to that of a non-transgenic plant, where the transgenic plant displays an altered leaf senescence phenotype, relative to a non-transgenic plant. The present invention relates to a mutant plant comprising an inactivated gene encoding S3H protein, where the mutant plant displays a premature or precocious leaf senescence phenotype, relative to a non-mutant plant. The present invention also relates to methods for promoting premature or precocious leaf senescence in a plant, delaying leaf senescence in a plant, and making a mutant plant having a decreased level of S3H protein compared to that of a non-mutant plant, where the mutant plant displays a premature or precocious leaf senescence phenotype relative to a non-mutant plant. The present invention also relates to inducing or promoting pathogen resistance in plants.

  PublisherOA PDF

• Ethylene controls cambium stem cell activity via promoting local auxin biosynthesis

  New Phytologist · 2023-06-07 · 16 citations

  articleOpen access

  The vascular cambium is the main secondary meristem in plants that produces secondary phloem (outside) and xylem (inside) on opposing sides of the cambium. The phytohormone ethylene has been implicated in vascular cambium activity, but the regulatory network underlying ethylene-mediated cambial activity remains to be elucidated. Here, we found that PETAL MOVEMENT-RELATED PROTEIN1 (RhPMP1), an ethylene-inducible HOMEODOMAIN-LEUCINE ZIPPER I transcription factor in woody plant rose (Rosa hybrida), regulates local auxin biosynthesis and auxin transport to maintain cambial activity. Knockdown of RhPMP1 resulted in smaller midveins and reduced auxin content, while RhPMP1 overexpression resulted in larger midveins and increased auxin levels compared with the wild-type plants. Furthermore, we revealed that Indole-3-pyruvate monooxygenase YUCCA 10 (RhYUC10) and Auxin transporter-like protein 2 (RhAUX2), encoding an auxin biosynthetic enzyme and an auxin influx carrier, respectively, are direct downstream targets of RhPMP1. In summary, our results suggest that ethylene promotes an auxin maximum in the cambium adjacent to the xylem to maintain cambial activity.

  PublisherOA PDFDOI

• Recent progresses in molecular postharvest biology

  Molecular Horticulture · 2022-08-10 · 2 citations

  editorialOpen access1st authorCorresponding
  PublisherOA PDFDOI

• Hypothesis: the subcellular senescence sequence of a mesophyll cell mirrors the cell origin and evolution

  Molecular Horticulture · 2022-12-06 · 2 citations

  letterOpen access1st authorCorresponding
  PublisherOA PDFDOI

• A positive feedback regulatory loop, SA-AtNAP-SAG202/SARD1-ICS1-SA, in SA biosynthesis involved in leaf senescence but not defense response

  Molecular Horticulture · 2022-06-17 · 18 citations

  articleOpen accessSenior author

  Salicylic acid (SA) is an important plant hormone that regulates defense responses and leaf senescence. It is imperative to understand upstream factors that regulate genes of SA biosynthesis. SAG202/SARD1 is a key regulator for isochorismate synthase 1 (ICS1) induction and SA biosynthesis in defense responses. The regulatory mechanism of SA biosynthesis during leaf senescence is not well understood. Here we show that AtNAP, a senescence-specific NAC family transcription factor, directly regulates a senescence-associated gene named SAG202 as revealed in yeast one-hybrid and in planta assays. Inducible overexpreesion of AtNAP and SAG202 lead to high levels of SA and precocious senescence in leaves. Individual knockout mutants of sag202 and ics1 have markedly reduced SA levels and display a significantly delayed leaf senescence phenotype. Furthermore, SA positively feedback regulates AtNAP and SAG202. Our research has uncovered a unique positive feedback regulatory loop, SA-AtNAP-SAG202-ICS1-SA, that operates to control SA biosynthesis associated with leaf senescence but not defense response.

  PublisherOA PDFDOI

• Correction: Recent progresses in molecular postharvest biology

  Molecular Horticulture · 2022-08-31

  erratumOpen access1st authorCorresponding
  PublisherOA PDFDOI

Recent grants

• Development and Use of an Innovative TASSEL Tagging System to Identify "Green Genes"

  NSF · $444k · 2005–2008

Frequent coauthors

• Cai‐Zhong Jiang

  University of California, Davis

  27 shared

• Yongfeng Guo

  Chinese Academy of Agricultural Sciences

  16 shared

• Richard M. Amasino

  University of Wisconsin–Madison

  10 shared

• Junping Gao

  China Agricultural University

  9 shared

• Nan Ma

  Heilongjiang Bayi Agricultural University

  9 shared

• Yonghong Li

  Shenzhen Polytechnic

  7 shared

• Yuehui He

  Peking University

  7 shared

• Liping Chen

  South China University of Technology

  6 shared

Education

• Ph.D. (Biochemistry), Biochemistry

  University of Wisconsin Madison

  1995