Assessing Loss of Regulatory Divergence, Genome–Transcriptome Incongruence, and Preferential Expression Switching in Abaca × Banana Backcrosses

The <i>Musa textilis</i> var. Abuab has high fiber quality (FQ) but is susceptible to abaca bunchy top virus (AbBTV); the <i>Musa balbisiana</i> var. Pacol has low FQ but is resistant against AbBTV. Their backcrosses (BC<sub>2</sub> and BC<sub>3</sub>)...

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Main Authors: Nelzo C. Ereful, Antonio G. Lalusin, Antonio C. Laurena
Format: Article
Language:English
Published: MDPI AG 2022-08-01
Series:Genes
Subjects:
Online Access:https://www.mdpi.com/2073-4425/13/8/1396
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author Nelzo C. Ereful
Antonio G. Lalusin
Antonio C. Laurena
author_facet Nelzo C. Ereful
Antonio G. Lalusin
Antonio C. Laurena
author_sort Nelzo C. Ereful
collection DOAJ
description The <i>Musa textilis</i> var. Abuab has high fiber quality (FQ) but is susceptible to abaca bunchy top virus (AbBTV); the <i>Musa balbisiana</i> var. Pacol has low FQ but is resistant against AbBTV. Their backcrosses (BC<sub>2</sub> and BC<sub>3</sub>) possess both desirable traits. Analysis using RNA-seq showed that the regulatory divergence of Abuab and Pacol is largely explained by cis differences with 27.4% and 22.3% if we are to assess it using BC<sub>2</sub> and BC<sub>3</sub>, respectively. Cis differences between the two genotypes are significantly reduced from BC<sub>2</sub> to BC<sub>3</sub> due to changes in genomic constitution. Trans, on the other hand, is robust to changes in allelic composition. All these are attributed to the loss of heterozygosity in BC<sub>3</sub> relative to BC<sub>2</sub>. Further analysis showed that both backcrosses exhibited genome-wide preferential expression of Pacol- over Abuab-specific alleles, despite the wider genetic presence of the latter in the hybrids. The ratio of the two genotype-specific expressed transcripts and the ratio of their corresponding genetic make-up are significantly disproportionate, a phenomenon that we refer to here as “genome–transcriptome incongruence”. We also observed preferential expression switching in which several genes prefer the Abuab- (or Pacol-) specific allele in BC<sub>2</sub> but switched to the Pacol- (or Abuab-) specific allele in the BC<sub>3</sub> genome.
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spelling doaj.art-5689de05f6944201b6297b8621f8b1142023-12-03T13:42:58ZengMDPI AGGenes2073-44252022-08-01138139610.3390/genes13081396Assessing Loss of Regulatory Divergence, Genome–Transcriptome Incongruence, and Preferential Expression Switching in Abaca × Banana BackcrossesNelzo C. Ereful0Antonio G. Lalusin1Antonio C. Laurena2Biochemistry Laboratory–Plant Physiology Laboratory, Institute of Plant Breeding, College of Agriculture and Food Science, University of the Philippines Los Baños, Laguna 4031, PhilippinesInstitute of Crop Science, College of Agriculture and Food Science, University of the Philippines Los Baños, Laguna 4031, PhilippinesPhilippine Genome Center for Agriculture, University of the Philippines Los Baños, Laguna 4031, PhilippinesThe <i>Musa textilis</i> var. Abuab has high fiber quality (FQ) but is susceptible to abaca bunchy top virus (AbBTV); the <i>Musa balbisiana</i> var. Pacol has low FQ but is resistant against AbBTV. Their backcrosses (BC<sub>2</sub> and BC<sub>3</sub>) possess both desirable traits. Analysis using RNA-seq showed that the regulatory divergence of Abuab and Pacol is largely explained by cis differences with 27.4% and 22.3% if we are to assess it using BC<sub>2</sub> and BC<sub>3</sub>, respectively. Cis differences between the two genotypes are significantly reduced from BC<sub>2</sub> to BC<sub>3</sub> due to changes in genomic constitution. Trans, on the other hand, is robust to changes in allelic composition. All these are attributed to the loss of heterozygosity in BC<sub>3</sub> relative to BC<sub>2</sub>. Further analysis showed that both backcrosses exhibited genome-wide preferential expression of Pacol- over Abuab-specific alleles, despite the wider genetic presence of the latter in the hybrids. The ratio of the two genotype-specific expressed transcripts and the ratio of their corresponding genetic make-up are significantly disproportionate, a phenomenon that we refer to here as “genome–transcriptome incongruence”. We also observed preferential expression switching in which several genes prefer the Abuab- (or Pacol-) specific allele in BC<sub>2</sub> but switched to the Pacol- (or Abuab-) specific allele in the BC<sub>3</sub> genome.https://www.mdpi.com/2073-4425/13/8/1396abaca (<i>M. textilis</i>)allelic imbalanceregulatory divergencebanana (<i>M. balbisiana</i>)allele-specific expression
spellingShingle Nelzo C. Ereful
Antonio G. Lalusin
Antonio C. Laurena
Assessing Loss of Regulatory Divergence, Genome–Transcriptome Incongruence, and Preferential Expression Switching in Abaca × Banana Backcrosses
Genes
abaca (<i>M. textilis</i>)
allelic imbalance
regulatory divergence
banana (<i>M. balbisiana</i>)
allele-specific expression
title Assessing Loss of Regulatory Divergence, Genome–Transcriptome Incongruence, and Preferential Expression Switching in Abaca × Banana Backcrosses
title_full Assessing Loss of Regulatory Divergence, Genome–Transcriptome Incongruence, and Preferential Expression Switching in Abaca × Banana Backcrosses
title_fullStr Assessing Loss of Regulatory Divergence, Genome–Transcriptome Incongruence, and Preferential Expression Switching in Abaca × Banana Backcrosses
title_full_unstemmed Assessing Loss of Regulatory Divergence, Genome–Transcriptome Incongruence, and Preferential Expression Switching in Abaca × Banana Backcrosses
title_short Assessing Loss of Regulatory Divergence, Genome–Transcriptome Incongruence, and Preferential Expression Switching in Abaca × Banana Backcrosses
title_sort assessing loss of regulatory divergence genome transcriptome incongruence and preferential expression switching in abaca banana backcrosses
topic abaca (<i>M. textilis</i>)
allelic imbalance
regulatory divergence
banana (<i>M. balbisiana</i>)
allele-specific expression
url https://www.mdpi.com/2073-4425/13/8/1396
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