Optimisation of a somatic embryogenesis and transformation protocol for farmer-preferred cassava cultivars in Kenya

Cassava ( Manihot esculenta Crantz ) is a major food crop in developing countries, and holds potential for industrial use. It is, however, affected by various biotic and abiotic stresses that greatly affect its production. The existing regeneration and transformation protocols are not compatible with all cassava cultivars, thus efficient and robust transformation and regeneration protocols for farmer-preferred cultivars need to be optimised for ease of transfer of novel genes. The objective of this study was to develop an efficient transformation and regeneration protocol for a farmer-preferred Kenyan cassava cultivar. We cultured immature leaf lobe and stem explants on Murashige and Skoog (MS) medium, supplemented with varying concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D), Picloram and \ue1-naphthalene acetic acid (NAA). Plants were recovered on media with 6-Benzylaminopurine (BAP) and GA3 under a 16 hour light/8 hour darkness photoperiod regime. Results showed high regeneration and transformation frequencies for both cultivars. High frequencies of callus induction (>98%) for both cultivars, were obtained when 2,4-D and Picloram were used. Similarly, both auxins initiated somatic embryogenesis, with Picloram producing the highest frequency of somatic embryos (>92%) in TMS 60444, using stem explants. Gus assays revealed high frequencies of transformation of >77% (TMS 60444) and 60% (Kibanda meno mkubwa). This protocol offers promising perspectives for rapid improvement of these cultivars and, therefore, provides a platform for cleaning planting materials, as well as cassava genetic improvement programmes such as control of viral diseases.Le manioc ( Manihot esculenta Crantz ) est une culture vivri\ue8re de grande importance pour les pays en d\ue9veloppement, avec un potentiel pour l\u2019usage industriel. N\ue9anmoins, le manioc est sujet \ue0 des stress d\u2019origines biotique et abiotique, affectant sa production. Les protocoles de r\ue9g\ue9n\ue9ration et de transformation existante ne sont pas compatibles avec toutes les accessions de manioc. Ainsi, il est n\ue9cessaire de d\ue9velopper des protocoles de r\ue9g\ue9n\ue9ration et de transformation efficaces pour les accessions adopt\ue9es par les paysans, afin de faciliter les transferts de g\ue8nes d\u2019int\ue9r\ueat. L\u2019objectif de cet etude \ue9tait de d\ue9velopper un protocole de r\ue9g\ue9n\ue9ration et de transformation adapte a la vari\ue9t\ue9 de manioc. Des feuilles et tiges immatures ont \ue9t\ue9 cultiv\ue9es sur des media Murashige et Skoog (MS), auxquels diff\ue9rentes concentrations de 2,4-dichlorophenoxyacetic acide (2,4-D), Picloram et \ue1-naphtal\ue8ne ac\ue9tique acide (NAA). Les plantes ont \ue9t\ue9 recouvertes de 6-Benzylaminopurine (BAP) et GA3 sous une photop\ue9riode de 16h jour/8h nuit. Les r\ue9sultats ont montr\ue9 des fr\ue9quences \ue9lev\ue9es de r\ue9g\ue9n\ue9ration et de transformation pour les deux cultivars Kibanda meno mkubwa et TMS 60444. Des fr\ue9quences \ue9lev\ue9es d\u2019induction de callosit\ue9s (>98%) ont \ue9t\ue9 obtenues pour les deux cultivars, lorsque 2,4-D et Picloram ont \ue9t\ue9 utilis\ue9s. De la m\ueame fa\ue7on, les deux embryogen\ue8ses somatiques initi\ue9es a l\u2019auxine, avec des explants de tiges et du Picloram ont exhibe la fr\ue9quence la plus \ue9lev\ue9e d\u2019embryon somatique (>92%) en TMS 60444. Des essais de Gus ont r\ue9v\ue9l\ue9s des fr\ue9quences \ue9lev\ue9es de transformation >77% (TMS 60444) et 60% (Kibanda meno mkubwa). Ce protocole offre des perspectives pour l\u2019am\ue9lioration rapide de ces cultivars, et par cons\ue9quent, fournit une plateforme pour la production de mat\ue9riels de culture propres, mais aussi servira d\u2019outil dans les programmes d\u2019am\ue9lioration g\ue9n\ue9tique visant la lutte contre les maladies virales

Can children take advantage of nao gaze-based hints during gameplay?

This paper presents a study that analyzes the effects of robots' gaze hints on children's performance in a card-matching game. We conducted a within-subjects study, in which children played a card matching game "Memory" in the presence of a robot tutor in two sessions. In one session, the robot gave hints to help the child find matching cards by looking at the correct match and, in the other session, the robot only looked at the child and did not give them any help. Children performance was measured using the number of tries and overall time used to complete the game. Our findings show that the use of gaze hints (help condition) made the matching task significantly easier and that children used significantly fewer tries than without help