**Author details**

deprived condition [97]. Meanwhile, brassinosteroid receptor mutants such as *det2* (*deettiolated 2*) and *bri1* (*brassinosteroid insensitive*) were more sensitive to the ABA. Consequently, synthesis of GAs was also deeply affected [98]. This result signifies the importance of brassinosteriods

Auxins are generally known for their roles in the root induction. Ogawa et al. reported upregulation of a number of auxin biosynthetic genes and genes encoding for auxin-carrying proteins in response to exogenous GA4 application [91]. The GA was well known to promote the auxin synthesis and the transportation of ethylene. Chiwocha et al. (2005) evidenced that the interaction of ethylene biosynthetic genes with the auxin signaling genes such as *axr1* and *axr2* was mediated by GA [99]. The BIG-gene, named due to its large size, encodes the calossin/ pushover protein involved in the efflux transportation of auxin [100]. Repressor of RGA proteins by the GA can be delayed by the attenuating auxin transportation or signaling [101]. Contrastingly, recent study in *Arabidopsis* by Lui et al. observed that the mutants of auxin receptors or biosynthesis genes showed the dramatic release of seed dormancy. This auxinmediated seed dormancy was coordinated with ABA signaling [102]. Both GA and ABA have strong influence on auxins during germination and dormancy, respectively. This kind of crosstalk between the hormones helps in the flexibility of the embryo/seeds in response to the

During the developmental stage of embryos into the vigorous photoautrotropic organisms, numerous metabolic processes are activated and they include oxidation of proteins, cellular structural changes, and synthesis of macromolecules. The cascade of metabolic process ceases with the development of the radicle governed by the well-directed ROS accumulation. Interlinked relation between the GA and ABA aids in the proper development of the embryo, seed filling, desiccation tolerance, imbibition, hydrolysis, temporal and spatial distribution of ROS, proteolysis, and radicle protrusion. The recent evidences suggest that ABA-GA crosstalk with other phytohormones, such as ethylene, brassinosteroids and auxin, could play a vital role in the development of the seed. The important components other than the free radicals

linked with the GA-ABA and their responses to the light and temperature could be one of the

Prabhakaran Soundararajan and Abinaya Manivannan were supported by a scholarship from

interesting areas getting more attention on the seed research.

the BK21 Plus Program, the Ministry of Education, Republic of Korea.

, H2O2, and •OH pertaining to the seed potential is the NO. Tapping of the NO

in the GA synthesis for successful seed germination.

88 New Challenges in Seed Biology - Basic and Translational Research Driving Seed Technology

**5.3. Auxin**

environmental stimuli.

**6. Conclusions**

such as O2


**Acknowledgements**

Prabhakaran Soundararajan1 , Abinaya Manivannan1 and Byoung Ryong Jeong1,2,3\*

\*Address all correspondence to: brjeong@gmail.com

1 Division of Applied Life Science (BK21 Plus), Graduate School, Gyeongsang National University, Jinju, Republic of Korea

2 Institute of Agriculture and Life Science, Gyeongsang National University, Jinju, Republic of Korea

3 Research Institute of Life Science, Gyeongsang National University, Jinju, Republic of Ko‐ rea
