Identification of Genes Related to Endosperm Balance Number Insensitivity in Paspalum notatum

Abstract

The endosperm balance number (EBN) theory states that genomic contribution ratio should be kept at 2:1 maternal/paternal (m:p) ratio for normal endosperm development. However, the endosperm formation in apomictic Paspalum notatum Flüggé does not depend on the EBN. The aim of this work was to characterize gene expression during seed formation from apomictic and sexual P. notatum using complementary DNA‐amplified fragment length polymorphism methodology. To induce the formation of seeds with different m:p genomic ratios, crosses were made between genotypes with different ploidy levels and reproductive modes. RNA was isolated from ovaries 24 h after pollination, when maximum endosperm growth rate was expected. Some of the 49 differentially expressed transcript‐derived fragments (DETDFs) provided relevant information. Three of those were found in ovaries of apomictic plants with an EBN different from 2:1. A DETDF was predicted to be involved in sucrose metabolism during the accumulation of hexose and starch in the endosperm and might be related to EBN insensitivity. Twenty‐two DETDFs were found in crosses where sexual plants were used as the female parent and the predicted m:p ratio was not 2:1. One of those was related to the failure of fusion of the polar nuclei in Arabidopsis thaliana (L.) Heynh. Finally, three transcripts presented similarity with a casein kinase II that regulates the accumulation of storage products in seeds of A. thaliana. Both processes might be involved in endosperm development in P. notatum.

PRODUCCIÓN DE HÍBRIDOS INTERESPECÍFICOS ENTRE Nierembergia ericoides Y Nierembergia linariaefolia MEDIANTE LA APLICACIÓN DE TÉCNICAS DE RESCATE EMBRIONARIO

“…Desbalances de este tipo son descriptos por Masuelli y Camadro (1997) en cruzamientos interespecíficos de especies salvajes del género Solanum, donde el desbalance del número endospérmico juega un rol principal en la interrupción del desarrollo del endosperma seguido por una hiperplasia en el endotelio. Al respecto, la relación genómica materna:paterna 2:1 en el endosperma ha sido considerada una condición necesaria para el éxito del desarrollo del endosperma tanto en cruzamientos intraespecíficos como interespecíficos (Depetris, 2018). Teniendo en cuenta estudios cromosómicos en el género Nierembergia, donde se reporta que N. ericoides tiene 2n = 2x = 18 y N. linariaefolia con 2n = 2x = 16 (Acosta et al, 2006), la interrupción del crecimiento del embrión se debería al cese del desarrollo del endosperma debido al desbalance del número endospérmico, provocando la falta de nutrición del embrión y el posterior aborto como consecuencia.…”

How to Become an Apomixis Model: The Multifaceted Case of Paspalum

“…A second transcriptome analysis using the same methodology revealed 65 new transcripts differentially expressed at the premeiosis/meiosis stage [ 58 ], including members of the LORELEI family ( GAP1 ) [ 58 , 96 ], the S-adenosyl-L-methionine-dependent methyltransferase family ( TRIMETHYLGUANOSINE SYNTHASE1 ) [ 58 , 97 ]; the MAP3K YODA family ( QUI-GON JINN [ 58 , 98 ] as well as several retrotransposons carrying transduplicated gene segments [ 58 , 99 ], sometimes involving apomixis-associated genes like SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE ( SERK ) [ 58 , 99 , 100 ], and long-noncoding transcripts possibly involved in splicing regulation [ 101 ]. Furthermore, differential expression analyses during early seed development (3–24 h after pollination) revealed ≈100 DETs possibly associated with the unbalanced genomic contribution found in pseudogamous endosperms (4:1), including transcripts related with transcription regulation, signal transduction (e.g., lectin-like protein kinase and CK2 protein kinase α 1), growth/division, and response to changes in the extracellular ATP levels [ 102 , 103 ].…”

Endosperm variability: from endoreduplication within a seed to higher ploidy across species, and its competence

“…Also, regulatory mechanisms modulated at the transcriptional, translational and post-translational levels dissecting the apomictic trait, including epigenetic regulation, signal transduction and evolutionary aspects have been covered in detail (Ortiz et al, 2013; Brukhin, 2017; Schmidt, 2020). Notably, most of the genetic or molecular mechanisms associated with apomictic traits have been reported for the genus Paspalum (Quarin, 1999; Labombarda et al, 2002; Laspina et al, 2008; Polegri et al, 2010; Ortiz et al, 2013, 2017; Podio et al, 2014a; Felitti et al, 2015; Siena et al, 2016; Bocchini et al, 2018; Depetris et al, 2018; Mancini et al, 2018; Ochogavía et al, 2018; de Oliveira et al, 2020). These details will be of significant help in mining the genes associated with apomictic behaviour in other species as well, based on homology, using sequences obtainable through next-generation sequencing (NGS) tools, followed by further functional validation.…”