Evaluation of Abiotic Stress Resistance in Mutated Populations of Cauliflower (Brassica oleracea var. botrytis)

Abstract

An efficient in vitro screening method has been developed for cauliflower to create NEU and NMU induced mutant lines selected on hydroxyproline containing medium. Mutant lines and control plants were sub-cultured many times on maintenance medium and stored at 5°C for 2 years and then tested for salt and hydroxyproline resistance as in vitro and in vivo plants. In vitro shoot tips were also sub-cultured to media containing hydroxyproline and NaCl for 28 days and then assessed for their leaf proline content. Non-acclimated and acclimated in vivo plants were also assessed for resistance to freezing. Populations of control and selected lines were created by mass pollination and subsequently tested for their NaCl and frost resistance. Control plants had little or no NaCl or hydroxyproline resistance whilst selected plants showed varying degrees of resistance. In vitro and in vivo responses of selected lines were correlated. Leaf proline content was increased markedly in the mutant lines and the greatest proline contents occurred following NaCl stress with the most respondent line having 100-fold levels compared to the controls. Both non-acclimated and acclimated selected lines showed improved frost resistance over controls. Improvements in frost resistance were heritable but improvements in NaCl resistance were not. The results clearly demonstrated that NaCl, frost and hydroxyproline resistance were stable traits over repeated in vitro sub-cultures and prolonged low temperature storage. A complete range of mutants with single, double or triple resistance traits were produced. The level of resistance however was not necessarily correlated with the level of proline and some lines showed resistance without elevated proline. It is concluded that elevated proline is not essential for improved resistance to abiotic stress in cauliflower, but where it does occur it does improve resistance.

Chemically Induced Mutants of <i>Brassica oleracea var. botrytis</i> Maintained Stable Resistance to Drought and Salt Stress after Regeneration and Micropropagation

“…All of the mutants showed higher resistance compared to the control clone. These results confirm the previous findings of Fuller et al [15] who reported 80% damage for control population and signifycant degree of resistance with less than 50% damage for selected population. Kingsbury et al [33] reported that sensitive species were more impaired by salt stress than resistant one due to osmotic shock.…”

“…Fuller et al [15] reported that cauliflower in-vivo having the damage of greenness of leaf discs less than 50% showing significant degree of resistance. Following this criteria at day 5 of NaCl treatment, the in-vivo mutants K1, K9, K11, K19, and K21 showed less than 50% loss of colour and therefore showed salt resistance, while others showed a colour change of 50% or more and were classified as moderate and sensitive to NaCl.…”

“…A population of nonmutated/selected control clones was also prepared from the same curd materials. For the present investigation, eight highly tolerant (to drought and salt stress) mutants were selected on the bases of previous screening of mutated population by Fuller et al [15]. A set of the in-vitro clones were transferred to in-vivo condition through weaning process.…”

“…In previous study the cauliflower mutants were created in-vitro using chemical mutagens (NEU and NMU) and screening was mad for selection of abiotic stress tolerant mutants and selected mutants were denoted as S1, S2, S3 and so on [15]. The mutant lines and control plants were maintained in-vitro through shoot tips sub-culturing.…”

Influence of PEG generated osmotic stress on shoot regeneration and some biochemical parameters in Lathyrus culture

“…Due to these properties the level of proline accumulated could be a basis for selection of water stress-tolerant plants (Rai et al 2011). In many studies, plants exposed to water deficit that enhanced the proline content were identified as tolerant to drought (Fuller et al 2006;Bidabadi et al 2012;Sultan et al 2012). Tyagi et al (1999) recorded a 65-fold increase in proline content in leaves and 56-fold in stems of 7-days-old grass pea seedlings exposed to drought stress.…”