Molecular Mechanisms Governing Shade Responses in Maize

Abstract

22Light is one of the most important environmental factors affecting plant growth and 23 development. Plants use shade avoidance and shade tolerance strategies to adjust 24 their growth and development thus increase their success in the competition for 25 incoming light. To investigate the mechanism of shade responses in maize (Zea mays), 26 we examined the anatomical and transcriptional dynamics of the early shade response 27 in seedlings of the B73 inbred line. Transcriptome analysis identified 912 differentially 28 expressed genes, including genes involved in light signaling, auxin responses, and cell 29 elongation pathways. Grouping transcription factor family genes and performing 30 enrichment analysis identified multiple types of transcription factors that are 31 differentially regulated by shade and predicted putative core genes responsible for 32 regulating shade avoidance syndrome. For functional tests, we ectopically over-33 expressed ZmHB53, a type II HD-ZIP transcription factor gene significantly induced by 34 shade, in Arabidopsis thaliana. Transgenic Arabidopsis plants overexpressing 35 ZmHB53 exhibited narrower leaves, earlier flowering, and enhanced expression of 36 shade-responsive genes, suggesting that ZmHB53 participates in the regulation of 37 shade responses in maize. This study increases our understanding of the regulatory 38 network of the shade response in maize and provides a useful resource for maize 39 genetics and breeding. 40

Transcriptional analyses of maize leaves in response to high‐density planting

“…In the field, the effect of HDP is similar to that of shading (i.e., light quantity and quality change and photosynthesis decreases when plants are shaded during vegetative and reproductive stages) (Horvath et al, 2018(Horvath et al, , 2019Ma et al, 2018;Mckenzie-Gopsill et al, 2020;Rajcan et al, 2004;Shi et al, 2019). Our data showed that genes encoding photosynthesis and carbohydrate-related processes were significantly downregulated in the lower leaves under HDP (Supplemental Table S8), indicating that high planting density stress might induce plants to regulate environmental fitness at the cost of repressing the genes encoding photosynthesis-related processes.…”

Comparative analysis of two kinds of garlic seedings: qualities and transcriptional landscape

“…Interestingly, one AsaPIF gene was upregulated and one AsaHY5 gene was downregulated in blanched seedlings (Table S1). Homeobox domain (HD) TFs in maize (Zea mays) may play both negative and positive roles in the regulation of axillary bud development [48]. Notably, we identified eight upregulated and four downregulated genes encoding HD TFs in blanched seedlings relative to green seedlings (Table S9).…”

“…Light, shade, and darkness all act as signals to regulate phytohormone levels, signaling pathways and transcription factors expression to affect plant development [39,47,48,50,[82][83][84][85]. However, the mechanism by which light quality affects allicin synthesis remains unclear.…”

“…Yield is also an important factor in the growth of garlic seedlings. Previous studies showed that when grown under darkness or low-light conditions, seedlings rapidly elongate their hypocotyl (for dicots) or mesocotyl (in monocots) to rapidly reach the light above the soil surface [44] by modulating the expression of many genes [45][46][47][48][49][50].…”