Biology subjects

Patil, N. S.

Publications and source records attributed to Patil, N. S..

3 recordsLinked to original sources

bioRxiv2025

MicroRNA166-HD-ZIP III module impacts tuber shape, color and productivity in potato

Tuber shape and size are important traits in potato. Although several factors governing tuberization have been well studied, the molecular mechanisms regulating the tuber shape and size are still elusive. Here, we demonstrate that suppression of miR166, which targets class III HD-ZIP transcription factors, alters tuber morphology and productivity in potato. Target mimicry of miR166 (MIM166) in Solanum tuberosum ssp. Andigena resulted in elongated, pigmented tubers with reduced yield under short-day conditions. Transcriptome profiling of the tuberizing stolons - swollen head vs. stalk revealed differential expression of auxin-, cytokinin-, and gibberellin-associated genes, consistent with altered hormone levels. The coloured tubers from MIM166 line exhibited differential accumulation of cyanidin 3-glucoside, pelargonidin 3-glucoside, and delphinidin 3-glucoside. Tuber productivity in these lines was reduced possibly due to the decreased expression of SWEET11b and distorted vascular structures. Further, the miR166 target-StREVOLUTA exhibited dynamic expression during stolon-to-tuber transition, and could modulate StYUCCA7 expression, an auxin biosynthesis gene. Increased pigmentation and auxin accumulation in MIM166, reduced expression of auxin biosynthesis genes in REVOLUTA antisense, and low tuber yield collectively suggest miR166-REV as a regulatory module of auxin homeostasis in differentiating stolons that influences tuber morphology. These results reveal a previously unrecognized miRNA-mediated pathway governing storage organ shape, and extends the functional scope of the miR166-HD-ZIP III module beyond organ polarity. Significance statementLimited studies describe the molecular mechanisms regulating tuber shape in storage organ development. Here, we show that the miR166-REVOLUTA-auxin network has significant regulatory roles in potato development, influencing tuber shape, pigmentation, and productivity. These findings provide insights into molecular control of tuber morphology, uncover hitherto unknown functions of the miR166-REVOLUTA module in tuber crops, and broadens our understanding of miR166-mediated developmental regulation in plants.

plant biology↗

bioRxiv2024

A model of task-level human stepping regulation yields semistable walking

A simple lateral dynamic walker, with swing leg dynamics and three adjustable input parameters, is used to study how motor regulation affects frontal plane stepping. Motivated by experimental observations and phenomenological models, we imposed task-level multiobjective regulation targeting the walkers optimal lateral foot placement at each step. The regulator prioritizes achieving step width and lateral body position goals to varying degrees by choosing a mixture parameter. Our model thus integrates a lateral mechanical template, which captures fundamental mechanics of frontal-plane walking, with a lateral motor regulation template, an empirically verified model of how humans manipulate lateral foot placements in a goal-directed manner. The model captures experimentally observed stepping fluctuation statistics and demonstrates how linear empirical models of stepping dynamics can emerge from first-principles nonlinear mechanics. We find that task-level regulation gives rise to a goal equivalent manifold in the systems extended state space of mechanical states and inputs, a subset of which contains a continuum of period-1 gaits forming a semistable set: perturbations off of any of its gaits result in transients that return to the set, though typically to different gaits.

bioengineering↗

bioRxiv2022

Viability, task switching, and fall avoidance of the simplest dynamic walker

Humans display great versatility when performing goal-directed tasks while walking. However, the extent to which such versatility helps with fall avoidance remains unclear. We recently demonstrated a functional connection between the motor regulation needed to achieve task goals (e.g. maintaining walking speed) and a simple walkers ability to reject large disturbances. Here, for the same model, we identify the viability kernel--the state space region in which the walker can step forever via at least one sequence of push-off inputs per state. We further find that only a few basins of attraction of the speed-regulated walkers steady-state gaits can fully cover the viability kernel. This highlights a potentially important role of task-level motor regulation in fall avoidance. Therefore, we posit an adaptive hierarchical control/regulation strategy that switches between different task-level regulators to avoid falls. Our hierarchical task switching controller only requires a target value of the regulated observable--a task switch--at each walking step, each chosen from a small, predetermined collection. Because humans have typically already learned to perform such tasks during nominal walking conditions, this suggests that the information cost of biologically implementing such controllers for the nervous system, including cognitive demands in humans, could be relatively low.

bioengineering↗