Biology subjects

Miriyala, A.

Publications and source records attributed to Miriyala, A..

3 recordsLinked to original sources

bioRxiv2026

Lateralized dopaminergic neuron activity encodes goal-directed turning

Animals navigate through dynamic environments in search of resources. Dopaminergic systems are known to control movement and assign motivational value to cues, actions and outcomes, but how they guide ongoing locomotion towards a goal remains unclear. Here, we demonstrate that Drosophila mushroom body innervating dopaminergic neurons encode steering signals in world-centred (allocentric) and body-centred (egocentric) coordinates during goal-directed navigation. Thirsty flies track water vapour through upwind directed turning and locomotion, that persists for several seconds after the vapour disappears. We identified a population of rewarding dopaminergic neurons to be specifically required for maintaining directed tracking following vapour offset. Recordings of these dopaminergic neurons during behaviour revealed delayed bilateral activity that followed upwind-directed turning in allocentric coordinates. Moreover, lateralized ipsilateral activity in a subset of these dopaminergic neurons encode whether the fly turns left or right in egocentric coordinates. Finally, these dopaminergic neurons also exhibited increased ipsilateral activity when turning in the direction where water vapour was previously encountered. Therefore, activity of mushroom body dopaminergic neurons represents steering and direction-specific actions that together maintain goal-directed tracking in turbulent environments.

neuroscience↗

bioRxiv2022

Temporal responses of bumblebee gustatory neurons encode sugar identity

The sense of taste permits the recognition of valuable nutrients and the avoidance of potential toxins. Models of gustatory coding propose that within modalities (e.g. sweet, bitter, etc.), taste ligands are not distinct stimuli. However, these models are based on data from mice or flies that have omnivorous, non-specialist diets. A specialist feeder might, however, be expected to have acuity within modality if stimulus resolution was critical to survival. Previously, we found that bumblebees have a specialized mechanism for sensing sugars whereby two gustatory receptor neurons (GRNs) within the galeal sensilla of the bees mouthparts exhibit burst of spikes. Here, we show that the temporal firing patterns of these GRNs separate sugars into four distinct groups that correlate with sugar nutritional value and palatability. We also identified a third GRN that responded to stimulation with relatively high concentrations of fructose, sucrose, and maltose. Sugars that were non-metabolizable or toxic suppressed the responses of bursting GRNs to sucrose. These abilities to encode information about sugar value are a refinement to the bumblebees sense of sweet taste that could be an adaptation that enables precise calculations of the nature and nutritional value of floral nectar.

neuroscience↗

bioRxiv2018

Marker-assisted pyramiding of two major broad-spectrum bacterial blight resistance genes, Xa21 and Xa33 into an elite maintainer line of rice, DRR17B

Bacterial blight (BB) disease reduces the yield of rice varieties and hybrids considerably in many tropical rice growing countries like India. The present study highlights the development of durable BB resistance into the background of an elite maintainer of rice, DRR17B, by incorporating two major dominant genes, Xa21 and Xa33 through marker-assisted backcross breeding (MABB). Through two sets of backcrosses, the two BB resistance genes were transferred separately to DRR17B. In this process, at each stage of backcrossing, foreground selection was carried out for the target resistance genes and for non-fertility restorer alleles concerning the major fertility restorer genes Rf3 and Rf4, using gene-specific PCR-based markers, while background selection was done using a set of 61 and 64 parental polymorphic SSR markers respectively. Backcross derived lines possessing either Xa21 or Xa33 along with maximum genome recovery of DRR17B were identified at BC3F1 generation and selfed to develop BC3F2s. Plants harboring Xa21 or Xa33 in homozygous condition were identified among BC3F2s and were intercrossed with each other to combine both the genes. The intercross F1 plants (ICF1) were selfed and the intercross F2 (ICF2) plants possessing both Xa21 and Xa33 in homozygous condition were identified with the help of markers. They were then advanced further by selfing until ICF4 generation. Selected ICF4 lines were evaluated for their resistance against BB with eight virulent isolates and for key agro-morphological traits. Six promising two-gene pyramiding lines of DRR17B with high level of BB resistance and agro-morphological attributes similar or superior to DRR17B with complete maintenance ability have been identified. These lines with elevated level of durable resistance may be handy tool for BB resistance breeding.

plant biology↗