Sorghum Root Epigenetic Landscape During Limiting Phosphorus Conditions

Abstract

Efficient acquisition and use of available phosphorus from the soil is crucial for plant growth, development, and yield. With an ever-increasing acreage of croplands with suboptimal available soil phosphorus, genetic improvement of sorghum germplasm for enhanced phosphorus acquisition from soil is crucial to increasing agricultural output and reducing inputs, while confronted with a growing world population and uncertain climate. Sorghum bicolor is a globally important commodity for food, fodder, and forage. Known for robust tolerance to heat, drought, and other abiotic stresses, its capacity for optimal phosphorus use efficiency (PUE) is still being investigated for optimized root system architectures (RSA). Whilst a few RSA-influencing genes have been identified in sorghum and other grasses, the epigenetic impact on expression and tissue-specific activation of candidate PUE genes remains elusive. Here, we present transcriptomic, epigenetic, and regulatory network profiling of RSA modulation in the BTx623 sorghum background in response to limiting phosphorus (LP) conditions. We show that during LP, sorghum RSA is remodeled to increase root length and surface area, likely enhancing its ability to acquire P. Global DNA 5-methylcytosine and H3K4 and H3K27 trimethylation levels decrease in response to LP, while H3K4me3 peaks and DNA hypomethylated regions contain recognition motifs of numerous developmental and nutrient responsive transcription factors that display disparate expression patterns between different root tissues (primary root apex, elongation zone, and lateral root apex). Suggesting that epigenetic shifts during growth on LP results in targeted gene expression in a tissue-specific manner that optimizes the RSA for improved P uptake.

Decoding the sorghum methylome: understanding epigenetic contributions to agronomic traits

“…Some studies have also found that the environment can induce changes in methylation. For example, a study on root system architecture found methylation variation associated with environmental stresses [ 108 ]; other studies have found that DNA methylome is stable under stresses [ 94 ].…”

Speculative World-Building, Modernity, and the Text in Crisis: An Ecological Reading of Renee Gladman’s Ravicka Novels

“…51 The novel's apocalyptic ending ("I see them now, I see the fires") 52 appears to relate as much to the narrative and syntactical scaffolding-"how words are ordered to create meaning, how moving through that order is a kind of unfolding"-as to a geopolitical environment that we are invited to read as allegorical, but which is grounded in untranslatability. 53 Gladman's novels posit a relationship-or what I earlier called a zone of translation-between the crumbling (or "migrating") buildings and the creation of fiction. 54 It is as if they literalized Walter Benjamin's idea: "Allegories are, in the realm of thoughts, what ruins are in the realm of things."…”