Autotetraploidization enhances drought stress tolerance in two apple cultivars

Abstract

Key message It reports relevant traits of diploid and autotetraploid apple plants ('Hanfu' and 'Gala') in response to drought. The differences indicate that apple plants ('Hanfu' and 'Gala') may differ in their response to drought stress depending on ploidy level. Abstract The induction of polyploidy ameliorates the adverse effects of drought in many plants. In this study, the tolerance responses of diploid and autotetraploid apple with two cultivars were compared under drought stress treatment induced by polyethylene glycol (PEG)-6000 in the laboratory. Autotetraploid apple plants were previously induced in vitro from the diploid apple (Malus 9 domestica, 2n = 2x = 34) cultivar 'Hanfu' and 'Gala' by colchicine treatment. In this study, we elucidated the effects of drought stress on apple by investigating the following parameters in leaves: relative water content (RWC), proline content, malondialdehyde (MDA) content and expression of key aquaporin genes. Under drought stress, autotetraploid apple had higher RWC and chlorophyll fluorescence parameters and lower levels of MDA and proline compared with diploid apple. Key aquaporins genes were induced in leaves in response to PEG6000 treatment, including MdPIP1;1 and MdTIP1;1. The expression of these genes induced under drought stress treatment, and the genes were expressed at lower levels in the autotetraploid than in the diploid. Our combined physiological and molecular data reveal that polyploidization can enhance drought tolerance in 'Hanfu' and 'Gala' apple.

Apple Autotetraploids with Enhanced Resistance to Apple Scab (Venturia inaequalis) Due to Genome Duplication-Phenotypic and Genetic Evaluation

“…The higher WUE of tetraploids may indicate their higher tolerance to water stress, which was confirmed by Zhang et al [ 42 ] and Hias et al [ 21 ] on physiological and/or molecular levels. Under drought stress, ‘Hanfu’ and ‘Gala’ apple tetraploids had higher relative water content (RWC) and chlorophyll fluorescence parameters, while the lower levels of malondialdehyde (MDA) and proline, as well as lower expression levels of key aquaporin genes, MdPIP1 ; 1 and MdTIP1 ; 1 , indicated that tetraploids had enhanced drought tolerance compared to diploids [ 42 ]. Unlike in our study, Xue et al [ 19 ] observed that all parameters of gas exchange and chlorophyll fluorescence were higher in apple tetraploids of the ‘Hanfu’ cultivar.…”

Tetraploid teak seedling was more tolerant to drought stress than its diploid seedling

“…Peningkatan ploidi sudah terbukti pada banyak tanaman dapat meningkatkan ukuran dan pertumbuhan tanaman Ye et al, 2010;Hummer, 2015). Laporan lain mengungkapkan bahwa tanaman tetraploid memiliki ketahanan terhadap kondisi kekurangan air yang lebih tinggi jika dibandingkan dengan tanaman diploidnya (Chandra & Dubey, 2010;Liu et al, 2011;Zhang et al, 2015). Namun demikian, sampai saat ini belum ada laporan mengenai tingkat ketahanan tanaman jati tetraploid terhadap cekaman kekeringan sehingga penelitian ini bertujuan untuk membandingkan tingkat ketahanan bibit jati tetraploid dengan yang diploid terhadap cekaman kekeringan.…”

The Variable Effect of Polyploidization on the Phenotype in Escallonia

“…Besides morphological changes, physiological changes, e.g., stress resistance and flowering period, are reported for polyploid plants (Levin, 2002 ; Van Laere et al, 2010 ; Regalado et al, 2017 ) due to an increase in genome flexibility (Levin, 2002 ). A change in drought tolerance was found in tetraploid Spathiphyllum (Van Laere et al, 2010 ), in autotetraploid Malus (Zhang et al, 2015 ) and in pentaploid Betula (Li et al, 1996 ). An increase in drought tolerance was found in Citrus (Ruiz et al, 2016 ).…”