Tomato Shade Avoidance: Unraveling Internode Elongation and Hormonal Harmony

Abstract

In a quest to unravel the intricate dance of plants with light, our journey begins with the pivotal role of light and plant growth general introduction. The competition among neighboring vegetation sparks the phenomenon of shade avoidance syndrome (SAS), driven by far-red light enrichment. Armed with a foundation of molecular insights from prior research on shade avoidance syndrome, our thesis sets sail into uncharted territory. Chapter 1 delves into the shade avoidance syndrome (SAs) in tomato cultivars M82 and Moneymaker, dissecting cellular developmental plasticity under white light and far-red supplemented conditions. Microscopy-based quantification zooms into the first internode, revealing significant cellular anatomy responses, setting the stage for deeper exploration in subsequent chapters. Chapter 2 explores the molecular mechanism with tissue specific signally in SAS. A time series RNAseq sheds light on auxin’s early role in internode elongation and identification of transcription factors, paving the way for Chapter 4’s exploration of hormones, identifying potential key regulators. The hormonal dynamics take center stage in Chapter 4, as we probe into auxin, gibberellins, and brassinosteroids during SAS. The study unveils complex interactions governing stem elongation, highlighting the nuanced influence of auxin, while GA and BR emerge as potent players. The intricate interplay of these hormones shapes plant responses to shade, emphasizing their crucial roles. Chapter 5 encapsulates a multidimensional exploration, examining cell expansion, the regulatory roles of transcription factors, and the dynamics of shade avoidance responses across 8 dicots. Pith elongation patterns, transcriptional regulation, and motif distribution offer a nuanced understanding of conserved regions, showcasing the interdisciplinary nature of plant biology.Our journey concludes with a spotlight on the distribution of dissimilar transcription factors across plant families, paving the way for future investigations. In the final chapter, we cast a broad perspective on the constraints of RNAseq analysis, hormone analysis, and evolutionary considerations. The discovery of a general conservation pattern between pith-specific expression in far-red across diverse species and transcription factor conservation opens avenues for deeper research. While our proposed linkage model awaits further confirmation, this ongoing exploration promises to unveil the molecular intricacies of plant responses to light, enriching our understanding of adaptation strategies.